sis_vga.c   [plain text]

/* $XFree86: xc/programs/Xserver/hw/xfree86/drivers/sis/sis_vga.c,v 1.46 2004/02/26 15:07:02 twini Exp $ */
/*
 * Mode setup and basic video bridge detection
 *
 * Copyright (C) 2001-2004 by Thomas Winischhofer, Vienna, Austria.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1) Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2) Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3) The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESSED OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Author: 	Thomas Winischhofer <thomas@winischhofer.net>
 *
 * Init() function for old series (except for TV and FIFO calculation)
 * previously based on code which is Copyright (C) 1998,1999 by Alan
 * Hourihane, Wigan, England
 */

#include "xf86.h"
#include "xf86_OSproc.h"
#include "xf86_ansic.h"
#include "xf86Version.h"
#include "xf86PciInfo.h"
#include "xf86Pci.h"

#include "sis.h"
#include "sis_regs.h"
#include "sis_dac.h"

static Bool  SISInit(ScrnInfoPtr pScrn, DisplayModePtr mode);
static Bool  SIS300Init(ScrnInfoPtr pScrn, DisplayModePtr mode);
static int   SISDoSense(ScrnInfoPtr pScrn, unsigned short type, unsigned short test);
static void  SISSense30x(ScrnInfoPtr pScrn);
static int   SIS6326DoSense(ScrnInfoPtr pScrn, int tempbh, int tempbl, int tempch, int tempcl);
static void  SISSense6326(ScrnInfoPtr pScrn);
static void  SiS6326TVDelay(ScrnInfoPtr pScrn, int delay);

const CARD8 SiS6326TVRegs1[14] = {
     0x00,0x01,0x02,0x03,0x04,0x11,0x12,0x13,0x21,0x26,0x27,0x3a,0x3c,0x43
};

const CARD8 SiS6326TVRegs1_NTSC[6][14] = {
    {0x81,0x3f,0x49,0x1b,0xa9,0x03,0x00,0x09,0x08,0x7d,0x00,0x88,0x30,0x60},
    {0x81,0x3f,0x49,0x1d,0xa0,0x03,0x00,0x09,0x08,0x7d,0x00,0x88,0x30,0x60},
    {0x81,0x45,0x24,0x8e,0x26,0x0b,0x00,0x09,0x02,0xfe,0x00,0x09,0x51,0x60},
    {0x81,0x45,0x24,0x8e,0x26,0x07,0x00,0x29,0x04,0x30,0x10,0x3b,0x61,0x60},
    {0x81,0x3f,0x24,0x8e,0x26,0x09,0x00,0x09,0x02,0x30,0x10,0x3b,0x51,0x60},  /* 640x400, 640x480 */
    {0x83,0x5d,0x21,0xbe,0x75,0x03,0x00,0x09,0x08,0x42,0x10,0x4d,0x61,0x79}   /* 640x480u */
};

const CARD8 SiS6326TVRegs2_NTSC[6][54] = {
    {0x11, 0x17, 0x03, 0x09, 0x94, 0x02, 0x05, 0x06, 0x09, 0x50, 0x0C,
     0x0C, 0x06, 0x0D, 0x04, 0x0A, 0x94, 0x06, 0x0D, 0x04, 0x0A, 0x94,
     0xFC, 0xDF, 0x94, 0x1F, 0x4A, 0x03, 0x71, 0x07, 0x97, 0x10, 0x40,
     0x48, 0x00, 0x26, 0xB6, 0x10, 0x5C, 0xEC, 0x21, 0x2E, 0xBE, 0x10,
     0x64, 0xF4, 0x21, 0x13, 0x75, 0x08, 0x31, 0x6A, 0x01, 0xA0},
    {0x11, 0x17, 0x03, 0x0A, 0x94, 0x02, 0x05, 0x06, 0x09, 0x50, 0x0C,
     0x0D, 0x06, 0x0D, 0x04, 0x0A, 0x94, 0x06, 0x0D, 0x04, 0x0A, 0x94,
     0xFF, 0xDF, 0x94, 0x1F, 0x4A, 0x03, 0x71, 0x07, 0x97, 0x10, 0x40,
     0x48, 0x00, 0x26, 0xB6, 0x10, 0x5C, 0xEC, 0x21, 0x2E, 0xBE, 0x10,
     0x64, 0xF4, 0x21, 0x13, 0x75, 0x08, 0x31, 0x6A, 0x01, 0xA0},
    {0x11, 0x17, 0x03, 0x0A, 0x94, 0x02, 0x05, 0x06, 0x09, 0x50, 0x0C,
     0x0D, 0x06, 0x0D, 0x04, 0x0A, 0x94, 0x06, 0x0D, 0x04, 0x0A, 0x94,
     0xFF, 0xDF, 0x94, 0x3F, 0x8C, 0x06, 0xCE, 0x07, 0x27, 0x30, 0x73,
     0x7B, 0x00, 0x48, 0x68, 0x30, 0xB2, 0xD2, 0x52, 0x50, 0x70, 0x30,
     0xBA, 0xDA, 0x52, 0xDC, 0x02, 0xD1, 0x53, 0xF7, 0x02, 0xA0},
    {0x11, 0x17, 0x03, 0x09, 0x94, 0x02, 0x05, 0x06, 0x09, 0x50, 0x0C,
     0x0C, 0x06, 0x0D, 0x04, 0x0A, 0x94, 0x06, 0x0D, 0x04, 0x0A, 0x94,
     0xDC, 0xDF, 0x94, 0x3F, 0x8C, 0x06, 0xCE, 0x07, 0x27, 0x30, 0x73,
     0x7B, 0x00, 0x48, 0x68, 0x30, 0xB2, 0xD2, 0x52, 0x50, 0x70, 0x30,
     0xBA, 0xDA, 0x52, 0x00, 0x02, 0xF5, 0x53, 0xF7, 0x02, 0xA0},
    {0x11, 0x17, 0x03, 0x09, 0x94, 0x02, 0x05, 0x06, 0x09, 0x50, 0x0C,
     0x0C, 0x06, 0x0D, 0x04, 0x0A, 0x94, 0x06, 0x0D, 0x04, 0x0A, 0x94,
     0xDC, 0xDF, 0x94, 0x3F, 0x8C, 0x06, 0xCE, 0x07, 0x27, 0x30, 0x73,
     0x7B, 0x00, 0x48, 0x68, 0x30, 0xB2, 0xD2, 0x52, 0x50, 0x70, 0x30,
     0xBA, 0xDA, 0x52, 0xDC, 0x02, 0xD1, 0x53, 0xF7, 0x02, 0xA0},
    {0x11, 0x17, 0x03, 0x09, 0x94, 0x02, 0x05, 0x06, 0x09, 0x50, 0x0C,  /* 640x480u */
     0x0C, 0x06, 0x0D, 0x04, 0x0A, 0x94, 0x06, 0x0D, 0x04, 0x0A, 0x94,
     0xDC, 0xDF, 0x94, 0xAF, 0x95, 0x06, 0xDD, 0x07, 0x5F, 0x30, 0x7E,
     0x86, 0x00, 0x4C, 0xA4, 0x30, 0xE3, 0x3B, 0x62, 0x54, 0xAC, 0x30,
     0xEB, 0x43, 0x62, 0x48, 0x34, 0x3D, 0x63, 0x29, 0x03, 0xA0}
};

const CARD8 SiS6326TVRegs1_PAL[6][14] = {
    {0x81,0x2d,0xc8,0x07,0xb2,0x0b,0x00,0x09,0x02,0xed,0x00,0xf8,0x30,0x40},
    {0x80,0x2d,0xa4,0x03,0xd9,0x0b,0x00,0x09,0x02,0xed,0x10,0xf8,0x71,0x40},
    {0x81,0x2d,0xa4,0x03,0xd9,0x0b,0x00,0x09,0x02,0xed,0x10,0xf8,0x71,0x40},  /* 640x480 */
    {0x81,0x2d,0xa4,0x03,0xd9,0x0b,0x00,0x09,0x02,0x8f,0x10,0x9a,0x71,0x40},  /* 800x600 */
    {0x83,0x63,0xa1,0x7a,0xa3,0x0a,0x00,0x09,0x02,0xb5,0x11,0xc0,0x81,0x59},  /* 800x600u */
    {0x81,0x63,0xa4,0x03,0xd9,0x01,0x00,0x09,0x10,0x9f,0x10,0xaa,0x71,0x59}   /* 720x540  */
};

const CARD8 SiS6326TVRegs2_PAL[6][54] = {
    {0x15, 0x4E, 0x35, 0x6E, 0x94, 0x02, 0x04, 0x38, 0x3A, 0x50, 0x3D,
     0x70, 0x06, 0x3E, 0x35, 0x6D, 0x94, 0x05, 0x3F, 0x36, 0x6E, 0x94,
     0xE5, 0xDF, 0x94, 0xEF, 0x5A, 0x03, 0x7F, 0x07, 0xFF, 0x10, 0x4E,
     0x56, 0x00, 0x2B, 0x23, 0x20, 0xB4, 0xAC, 0x31, 0x33, 0x2B, 0x20,
     0xBC, 0xB4, 0x31, 0x83, 0xE1, 0x78, 0x31, 0xD6, 0x01, 0xA0},
    {0x15, 0x4E, 0x35, 0x6E, 0x94, 0x02, 0x04, 0x38, 0x3A, 0x50, 0x3D,
     0x70, 0x06, 0x3E, 0x35, 0x6D, 0x94, 0x05, 0x3F, 0x36, 0x6E, 0x94,
     0xE5, 0xDF, 0x94, 0xDF, 0xB2, 0x07, 0xFB, 0x07, 0xF7, 0x30, 0x90,
     0x98, 0x00, 0x4F, 0x3F, 0x40, 0x62, 0x52, 0x73, 0x57, 0x47, 0x40,
     0x6A, 0x5A, 0x73, 0x03, 0xC1, 0xF8, 0x63, 0xB6, 0x03, 0xA0},
    {0x15, 0x4E, 0x35, 0x6E, 0x94, 0x02, 0x04, 0x38, 0x3A, 0x50, 0x3D,  /* 640x480 */
     0x70, 0x06, 0x3E, 0x35, 0x6D, 0x94, 0x05, 0x3F, 0x36, 0x6E, 0x94,
     0xE5, 0xDF, 0x94, 0xDF, 0xB2, 0x07, 0xFB, 0x07, 0xF7, 0x30, 0x90,
     0x98, 0x00, 0x4F, 0x3F, 0x40, 0x62, 0x52, 0x73, 0x57, 0x47, 0x40,
     0x6A, 0x5A, 0x73, 0x03, 0xC1, 0xF8, 0x63, 0xB6, 0x03, 0xA0},
    {0x15, 0x4E, 0x35, 0x6E, 0x94, 0x02, 0x04, 0x38, 0x3A, 0x50, 0x3D,  /* 800x600 */
     0x70, 0x06, 0x3E, 0x35, 0x6D, 0x94, 0x05, 0x3F, 0x36, 0x6E, 0x94,
     0xE5, 0xDF, 0x94, 0xDF, 0xB2, 0x07, 0xFB, 0x07, 0xF7, 0x30, 0x90,
     0x98, 0x00, 0x4F, 0x3F, 0x40, 0x62, 0x52, 0x73, 0x57, 0x47, 0x40,
     0x6A, 0x5A, 0x73, 0xA0, 0xC1, 0x95, 0x73, 0xB6, 0x03, 0xA0},
    {0x15, 0x4E, 0x35, 0x6E, 0x94, 0x02, 0x04, 0x38, 0x3A, 0x50, 0x3D,  /* 800x600u */
     0x70, 0x06, 0x3E, 0x35, 0x6D, 0x94, 0x05, 0x3F, 0x36, 0x6E, 0x94,
     0xE5, 0xDF, 0x94, 0x7F, 0xBD, 0x08, 0x0E, 0x07, 0x47, 0x40, 0x9D,
     0xA5, 0x00, 0x54, 0x94, 0x40, 0xA4, 0xE4, 0x73, 0x5C, 0x9C, 0x40,
     0xAC, 0xEC, 0x73, 0x0B, 0x0E, 0x00, 0x84, 0x03, 0x04, 0xA0},
    {0x15, 0x4E, 0x35, 0x6E, 0x94, 0x02, 0x04, 0x38, 0x3A, 0x50, 0x3D,  /* 720x540  */
     0x70, 0x06, 0x3E, 0x35, 0x6D, 0x94, 0x05, 0x3F, 0x36, 0x6E, 0x94,
     0xE5, 0xDF, 0x94, 0xDF, 0xB0, 0x07, 0xFB, 0x07, 0xF7, 0x30, 0x9D,
     0xA5, 0x00, 0x4F, 0x3F, 0x40, 0x62, 0x52, 0x73, 0x57, 0x47, 0x40,
     0x6A, 0x5A, 0x73, 0xA0, 0xC1, 0x95, 0x73, 0xB6, 0x03, 0xA0}
};

const CARD8 SiS6326CR[9][15] = {
     {0x79,0x63,0x64,0x1d,0x6a,0x93,0x00,0x6f,0xf0,0x58,0x8a,0x57,0x57,0x70,0x20},  /* PAL 800x600   */
     {0x79,0x4f,0x50,0x95,0x60,0x93,0x00,0x6f,0xba,0x14,0x86,0xdf,0xe0,0x30,0x00},  /* PAL 640x480   */
     {0x5f,0x4f,0x50,0x82,0x53,0x9f,0x00,0x0b,0x3e,0xe9,0x8b,0xdf,0xe7,0x04,0x00},  /* NTSC 640x480  */
     {0x5f,0x4f,0x50,0x82,0x53,0x9f,0x00,0x0b,0x3e,0xcb,0x8d,0x8f,0x96,0xe9,0x00},  /* NTSC 640x400  */
     {0x83,0x63,0x64,0x1f,0x6d,0x9b,0x00,0x6f,0xf0,0x48,0x0a,0x23,0x57,0x70,0x20},  /* PAL 800x600u  */
     {0x79,0x59,0x5b,0x1d,0x66,0x93,0x00,0x6f,0xf0,0x42,0x04,0x1b,0x40,0x70,0x20},  /* PAL 720x540   */
     {0x66,0x4f,0x51,0x0a,0x57,0x89,0x00,0x0b,0x3e,0xd9,0x0b,0xb6,0xe7,0x04,0x00},  /* NTSC 640x480u */
     {0xce,0x9f,0x9f,0x92,0xa4,0x16,0x00,0x28,0x5a,0x00,0x04,0xff,0xff,0x29,0x39},  /* 1280x1024-75  */
     {0x09,0xc7,0xc7,0x0d,0xd2,0x0a,0x01,0xe0,0x10,0xb0,0x04,0xaf,0xaf,0xe1,0x1f}   /* 1600x1200-60  */
};

/* Initialize a display mode on 5597/5598, 6326 and 530/620 */
static Bool
SISInit(ScrnInfoPtr pScrn, DisplayModePtr mode)
{
    SISPtr         pSiS = SISPTR(pScrn);
    SISRegPtr      pReg = &pSiS->ModeReg;
    vgaRegPtr      vgaReg = &VGAHWPTR(pScrn)->ModeReg;
    unsigned char  temp;
    int            mclk = pSiS->MemClock;
    int            offset;
    int            clock = mode->Clock;
    int            width = mode->HDisplay;
    int            height = mode->VDisplay;
    int            rate = SiSCalcVRate(mode);
    int            buswidth = pSiS->BusWidth;
    unsigned int   vclk[5];
    unsigned short CRT_CPUthresholdLow;
    unsigned short CRT_CPUthresholdHigh;
    unsigned short CRT_ENGthreshold;
    double         a, b, c;
    int            d, factor;
    int            num, denum, div, sbit, scale;
    BOOL	   sis6326tvmode, sis6326himode;

    PDEBUG(xf86DrvMsgVerb(pScrn->scrnIndex, X_INFO, 3, "SISInit()\n"));

    /* Save the registers for further processing */
    (*pSiS->SiSSave)(pScrn, pReg);

    /* Determine if chosen mode is suitable for TV on the 6326
     * and if the mode is one of our special hi-res modes.
     */
    sis6326tvmode = FALSE;
    sis6326himode = FALSE;
    if(pSiS->Chipset == PCI_CHIP_SIS6326) {
       if(pSiS->SiS6326Flags & SIS6326_HASTV) {
          if((pSiS->SiS6326Flags & SIS6326_TVDETECTED) &&
             ((strcmp(mode->name, "PAL800x600") == 0)   ||	/* Special TV modes */
              (strcmp(mode->name, "PAL800x600U") == 0)  ||
	      (strcmp(mode->name, "PAL720x540") == 0)   ||
              (strcmp(mode->name, "PAL640x480") == 0)   ||
	      (strcmp(mode->name, "NTSC640x480") == 0)  ||
	      (strcmp(mode->name, "NTSC640x480U") == 0) ||
	      (strcmp(mode->name, "NTSC640x400") == 0))) {
	     sis6326tvmode = TRUE;
          } else {
             pReg->sis6326tv[0x00] &= 0xfb;
          }
       }
       if((strcmp(mode->name, "SIS1280x1024-75") == 0) ||	/* Special high-res modes */
          (strcmp(mode->name, "SIS1600x1200-60") == 0)) {
	  sis6326himode = TRUE;
       }
    }

#ifdef UNLOCK_ALWAYS
    outSISIDXREG(SISSR, 0x05, 0x86);
#endif

    if(!pSiS->UseVESA) {
       pReg->sisRegs3C4[0x06] &= 0x01;
    }

    /* set interlace */
    if(!(mode->Flags & V_INTERLACE))  {
       offset = pSiS->CurrentLayout.displayWidth >> 3;
    } else  {
       offset = pSiS->CurrentLayout.displayWidth >> 2;
       if(!pSiS->UseVESA) {
          pReg->sisRegs3C4[0x06] |= 0x20;
       }
    }

    /* Enable Linear and Enhanced Gfx Mode */
    if(!pSiS->UseVESA) {
       pReg->sisRegs3C4[0x06] |= 0x82;
    }

    /* Enable MMIO at PCI Register 14H (D[6:5]: 11) */
    if(pSiS->oldChipset >= OC_SIS5597) {
       pReg->sisRegs3C4[0x0B] |= 0x60;
    } else {
       pReg->sisRegs3C4[0x0B] |= 0x20;
       pReg->sisRegs3C4[0x0B] &= ~0x40;
    }

    if(!pSiS->UseVESA) {

       /* Enable 32bit mem access (D7), read-ahead cache (D5) */
       pReg->sisRegs3C4[0x0C] |= 0x80;
       if(pSiS->oldChipset > OC_SIS6225) {
          pReg->sisRegs3C4[0x0C] |= 0x20;
       }

       /* Some speed-up stuff */
       switch(pSiS->Chipset) {
       case PCI_CHIP_SIS5597:
          /* enable host bus */
	  if(pSiS->NoHostBus) {
	     pReg->sisRegs3C4[0x34] &= ~0x08;
	  } else {
            pReg->sisRegs3C4[0x34] |= 0x08;
	  }
          /* fall through */
       case PCI_CHIP_SIS6326:
       case PCI_CHIP_SIS530:
          /* Enable "dual segment register mode" (D2) and "i/o gating while
           * write buffer is not empty" (D3)
           */
    	  pReg->sisRegs3C4[0x0B] |= 0x0C;
       }

       /* set colordepth */
       if(pSiS->Chipset == PCI_CHIP_SIS530) {
          pReg->sisRegs3C4[0x09] &= 0x7F;
       }
       switch(pSiS->CurrentLayout.bitsPerPixel) {
          case 8:
             break;
          case 16:
	     offset <<= 1;
	     if(pSiS->CurrentLayout.depth == 15)
	        pReg->sisRegs3C4[0x06] |= 0x04;
	     else
                pReg->sisRegs3C4[0x06] |= 0x08;
             break;
          case 24:
             offset += (offset << 1);
             pReg->sisRegs3C4[0x06] |= 0x10;
             pReg->sisRegs3C4[0x0B] |= 0x90;
             break;
          case 32:
             if(pSiS->Chipset == PCI_CHIP_SIS530) {
	        offset <<= 2;
	        if(pSiS->oldChipset != OC_SIS620) {
                   pReg->sisRegs3C4[0x06] |= 0x10;
	        }
                pReg->sisRegs3C4[0x0B] |= 0x90;
                pReg->sisRegs3C4[0x09] |= 0x80;
             } else return FALSE;
             break;
       }
    }

    /* save screen pitch for acceleration functions */
    pSiS->scrnOffset = pSiS->CurrentLayout.displayWidth *
                           ((pSiS->CurrentLayout.bitsPerPixel + 7) / 8);

    if(!pSiS->UseVESA) {

       /* set linear framebuffer addresses */
       switch(pScrn->videoRam)  {
          case 512:  temp = 0x00;  break;
          case 1024: temp = 0x20;  break;
          case 2048: temp = 0x40;  break;
          case 4096: temp = 0x60;  break;
          case 8192: temp = 0x80;  break;
          default:   temp = 0x20;
       }
       pReg->sisRegs3C4[0x20] = (pSiS->FbAddress & 0x07F80000) >> 19;
       pReg->sisRegs3C4[0x21] = ((pSiS->FbAddress & 0xF8000000) >> 27) | temp;

       /* Set screen offset */
       vgaReg->CRTC[0x13] = offset & 0xFF;

       /* Set CR registers for our built-in TV and hi-res modes */
       if((sis6326tvmode) || (sis6326himode)) {

	  int index,i;

	  /* We need our very private data for hi-res and TV modes */
	  if(sis6326himode) {
	     if(strcmp(mode->name, "SIS1280x1024-75") == 0)  index = 7;
	     else index = 8;
	  } else {
	     if(pSiS->SiS6326Flags & SIS6326_TVPAL) {
	        switch(width) {
	        case 800:
	           if((strcmp(mode->name, "PAL800x600U") == 0))
	      	      index = 4;
	           else
	              index = 0;
	           break;
	        case 720:
	           index = 5;
	           break;
	        case 640:
	        default:
	           index = 1;
	        }
	     } else {
	        switch(height) {
	        case 400:
	           index = 3;
	           break;
	        case 480:
	        default:
	           if((strcmp(mode->name, "NTSC640x480U") == 0))
	              index = 6;
	           else
	              index = 2;
	        }
	     }
          }
	  for(i=0; i<=5; i++) {
	     vgaReg->CRTC[i] = SiS6326CR[index][i];
	  }
          pReg->sisRegs3C4[0x12] = SiS6326CR[index][6];
	  vgaReg->CRTC[6] = SiS6326CR[index][7];
	  vgaReg->CRTC[7] = SiS6326CR[index][8];
	  vgaReg->CRTC[0x10] = SiS6326CR[index][9];
	  vgaReg->CRTC[0x11] = SiS6326CR[index][10];
	  vgaReg->CRTC[0x12] = SiS6326CR[index][11];
	  vgaReg->CRTC[0x15] = SiS6326CR[index][12];
	  vgaReg->CRTC[0x16] = SiS6326CR[index][13];
	  vgaReg->CRTC[9] &= ~0x20;
	  vgaReg->CRTC[9] |= (SiS6326CR[index][14] & 0x20);
	  pReg->sisRegs3C4[0x0A] = ((offset & 0xF00) >> 4) | (SiS6326CR[index][14] & 0x0f);

       } else {

          /* Set extended vertical overflow register */
          pReg->sisRegs3C4[0x0A] = ((offset & 0xF00) >> 4) |
                 (((mode->CrtcVTotal-2)     & 0x400) >> 10 ) |
                 (((mode->CrtcVDisplay-1)   & 0x400) >>  9 ) |
/*               (((mode->CrtcVSyncStart-1) & 0x400) >>  8 ) |  */
	         (((mode->CrtcVBlankStart-1)& 0x400) >>  8 ) |
/*               (((mode->CrtcVBlankStart-1)& 0x400) >>  7 );  */
                 (((mode->CrtcVSyncStart)   & 0x400) >>  7 );

          /* Set extended horizontal overflow register */
          pReg->sisRegs3C4[0x12] &= 0xE0;
          pReg->sisRegs3C4[0x12] |= (
              (((mode->CrtcHTotal >> 3) - 5)      & 0x100) >> 8 |
              (((mode->CrtcHDisplay >> 3) - 1)    & 0x100) >> 7 |
/*            (((mode->CrtcHSyncStart >> 3) - 1)  & 0x100) >> 6 |  */
              (((mode->CrtcHBlankStart >> 3) - 1) & 0x100) >> 6 |
              ((mode->CrtcHSyncStart >> 3)        & 0x100) >> 5 |
              (((mode->CrtcHBlankEnd >> 3) - 1)   & 0x40)  >> 2);
       }

#ifdef TWDEBUG
       xf86DrvMsg(0, X_INFO, "HDisplay %d HSyncStart %d HSyncEnd %d HTotal %d\n",
		mode->CrtcHDisplay, mode->CrtcHSyncStart,
		mode->CrtcHSyncEnd, mode->CrtcHTotal);
       xf86DrvMsg(0, X_INFO, "HBlankSt %d  HBlankE %d\n",
    		mode->CrtcHBlankStart, mode->CrtcHBlankEnd);

       xf86DrvMsg(0, X_INFO, "VDisplay %d VSyncStart %d VSyncEnd %d VTotal %d\n",
		mode->CrtcVDisplay, mode->CrtcVSyncStart,
		mode->CrtcVSyncEnd, mode->CrtcVTotal);
       xf86DrvMsg(0, X_INFO, "VBlankSt %d  VBlankE %d\n",
    		mode->CrtcVBlankStart, mode->CrtcVBlankEnd);
#endif

       /* enable (or disable) line compare */
       if(mode->CrtcVDisplay >= 1024)
          pReg->sisRegs3C4[0x38] |= 0x04;
       else
          pReg->sisRegs3C4[0x38] &= 0xFB;

       /* Enable (or disable) high speed DCLK (some 6326 and 530/620 only) */
       if( ( (pSiS->Chipset == PCI_CHIP_SIS6326) &&
             ( (pSiS->ChipRev == 0xd0) || (pSiS->ChipRev == 0xd1) ||
               (pSiS->ChipRev == 0xd2) || (pSiS->ChipRev == 0x92) ||
	       (pSiS->Flags & A6326REVAB) ) ) ||
           (pSiS->oldChipset > OC_SIS6326) ) {
         if( (pSiS->CurrentLayout.bitsPerPixel == 24) ||
             (pSiS->CurrentLayout.bitsPerPixel == 32) ||
             (mode->CrtcHDisplay >= 1280) )
            pReg->sisRegs3C4[0x3E] |= 0x01;
         else
            pReg->sisRegs3C4[0x3E] &= 0xFE;
       }

       /* We use the internal VCLK */
       pReg->sisRegs3C4[0x38] &= 0xFC;

       /* Programmable Clock */
       pReg->sisRegs3C2 = inb(SISMISCR) | 0x0C;

       if(pSiS->oldChipset <= OC_SIS86202) {
          /* TODO: Handle SR07 for clock selection */
	  /* 86C201 does not even have a programmable clock... */
	  /* pReg->sisRegs3C4[0x07] &= 0x??; */
       }

       /* Set VCLK */
       if((sis6326tvmode) || (sis6326himode)) {

          /* For our built-in modes, the calculation is not suitable */
          if(sis6326himode) {
             if((strcmp(mode->name, "SIS1280x1024-75") == 0)) {
	        pReg->sisRegs3C4[0x2A] = 0x5d;	/* 1280x1024-75 */
                pReg->sisRegs3C4[0x2B] = 0xa4;
             } else {
	        pReg->sisRegs3C4[0x2A] = 0x59;	/* 1600x1200-60 */
                pReg->sisRegs3C4[0x2B] = 0xa3;
             }
	     pReg->sisRegs3C4[0x13] &= ~0x40;
          } else {
             if(pSiS->SiS6326Flags & SIS6326_TVPAL) {
	        /* PAL: 31.500 Mhz */
	        if((strcmp(mode->name, "PAL800x600U") == 0)) {
   	           pReg->sisRegs3C4[0x2A] = 0x46;
                   pReg->sisRegs3C4[0x2B] = 0x49;
	        } else {
	           pReg->sisRegs3C4[0x2A] = 0xab;
                   pReg->sisRegs3C4[0x2B] = 0xe9;
	        }
	        pReg->sisRegs3C4[0x13] &= ~0x40;
	     } else {
	        /* NTSC: 27.000 Mhz */
	        if((strcmp(mode->name, "NTSC640x480U") == 0)) {
	           pReg->sisRegs3C4[0x2A] = 0x5a;
                   pReg->sisRegs3C4[0x2B] = 0x65;
	        } else {
	           pReg->sisRegs3C4[0x2A] = 0x29;
                   pReg->sisRegs3C4[0x2B] = 0xe2;
	        }
	        pReg->sisRegs3C4[0x13] |= 0x40;
	     }
          }

       } else if(SiS_compute_vclk(clock, &num, &denum, &div, &sbit, &scale)) {

          pReg->sisRegs3C4[0x2A] = (num - 1) & 0x7f ;
          pReg->sisRegs3C4[0x2A] |= (div == 2) ? 0x80 : 0;
          pReg->sisRegs3C4[0x2B] = ((denum - 1) & 0x1f);
          pReg->sisRegs3C4[0x2B] |= (((scale -1) & 3) << 5);

	  /* When setting VCLK, we should set SR13 first */
          if(sbit)
             pReg->sisRegs3C4[0x13] |= 0x40;
          else
             pReg->sisRegs3C4[0x13] &= 0xBF;

#ifdef TWDEBUG
	  xf86DrvMsg(0, X_INFO, "2a: %x 2b: %x 13: %x clock %d\n",
		pReg->sisRegs3C4[0x2A], pReg->sisRegs3C4[0x2B], pReg->sisRegs3C4[0x13], clock);
#endif

       } else {

          /* if SiS_compute_vclk cannot handle the requested clock, try sisCalcClock */
          SiSCalcClock(pScrn, clock, 2, vclk);

#define Midx    0
#define Nidx    1
#define VLDidx  2
#define Pidx    3
#define PSNidx  4	  

          pReg->sisRegs3C4[0x2A] = (vclk[Midx] - 1) & 0x7f;
          pReg->sisRegs3C4[0x2A] |= ((vclk[VLDidx] == 2) ? 1 : 0) << 7;

	  /* bits [4:0] contain denumerator */
          pReg->sisRegs3C4[0x2B] = (vclk[Nidx] - 1) & 0x1f;

          if(vclk[Pidx] <= 4){
             /* postscale 1,2,3,4 */
             pReg->sisRegs3C4[0x2B] |= (vclk[Pidx] - 1) << 5;
             pReg->sisRegs3C4[0x13] &= 0xBF;
          } else {
             /* postscale 6,8 */
             pReg->sisRegs3C4[0x2B] |= ((vclk[Pidx] / 2) - 1) << 5;
             pReg->sisRegs3C4[0x13] |= 0x40;
          }
          pReg->sisRegs3C4[0x2B] |= 0x80 ;   /* gain for high frequency */

       }

       /* High speed DAC */
       if(clock > 135000)
          pReg->sisRegs3C4[0x07] |= 0x02;

       if(pSiS->oldChipset > OC_SIS6225) {
          /* 1 or 2 cycle DRAM (set by option FastVram) */
          if(pSiS->newFastVram == -1) {
             if(pSiS->oldChipset == OC_SIS620) {
	        /* Use different default on the 620 */
                pReg->sisRegs3C4[0x34] |= 0x40;
	        pReg->sisRegs3C4[0x34] &= ~0x80;
             } else {
                pReg->sisRegs3C4[0x34] |= 0x80;
	        pReg->sisRegs3C4[0x34] &= ~0x40;
             }
          } else if(pSiS->newFastVram == 1)
             pReg->sisRegs3C4[0x34] |= 0xC0;
          else
             pReg->sisRegs3C4[0x34] &= ~0xC0;

          if(pSiS->oldChipset == OC_SIS620) {
             /* Enable SGRAM burst timing (= bit clear) on the 620 */
             if(pSiS->Flags & SYNCDRAM) {
                pReg->sisRegs3C4[0x35] &= ~0x20;
             } else {
                pReg->sisRegs3C4[0x35] |= 0x20;
             }
          }
       }

    } /* VESA */

    /* Logical line length */
    pSiS->ValidWidth = TRUE;
    pReg->sisRegs3C4[0x27] &= 0xCF;
    if(pSiS->CurrentLayout.bitsPerPixel == 24) {
         /* Invalid logical width */
         pReg->sisRegs3C4[0x27] |= 0x30;
         pSiS->ValidWidth = FALSE;
    } else {
	 switch(pScrn->virtualX * (pSiS->CurrentLayout.bitsPerPixel >> 3)) {
         case 1024:
               pReg->sisRegs3C4[0x27] |= 0x00;
               break;
         case 2048:
               pReg->sisRegs3C4[0x27] |= 0x10;
               break;
         case 4096:
               pReg->sisRegs3C4[0x27] |= 0x20;
               break;
         default:
               /* Invalid logical width */
               pReg->sisRegs3C4[0x27] |= 0x30;
               pSiS->ValidWidth = FALSE;
               break;
         }
    }

    /* Acceleration stuff */
    if(!pSiS->NoAccel) {
       pReg->sisRegs3C4[0x27] |= 0x40;   /* Enable engine programming registers */
       if( (pSiS->TurboQueue) &&	 /* Handle TurboQueue */
           (pSiS->oldChipset > OC_SIS6225) &&
 	   ( (pSiS->Chipset != PCI_CHIP_SIS530) ||
	     (pSiS->CurrentLayout.bitsPerPixel != 24) ) ) {
          pReg->sisRegs3C4[0x27] |= 0x80;        /* Enable TQ */
	  if((pSiS->Chipset == PCI_CHIP_SIS530) ||
	     ((pSiS->Chipset == PCI_CHIP_SIS6326 &&
	      (pSiS->ChipRev == 0xd0 || pSiS->ChipRev == 0xd1 ||
	       pSiS->ChipRev == 0xd2 || pSiS->ChipRev == 0x92 ||
	       pSiS->ChipRev == 0x0a || pSiS->ChipRev == 0x1a ||
	       pSiS->ChipRev == 0x2a || pSiS->ChipRev == 0x0b ||
	       pSiS->ChipRev == 0x1b || pSiS->ChipRev == 0x2b) ) ) ) {
	     /* pReg->sisRegs3C4[0x3D] |= 0x80;  */     /* Queue is 62K (530/620 specs) */
	     pReg->sisRegs3C4[0x3D] &= 0x7F;         /* Queue is 30K (530/620 specs) */
	  }
	  /* Locate the TQ at the beginning of the last 64K block of
	   * video RAM. The address is to be specified in 32K steps.
	   */
	  pReg->sisRegs3C4[0x2C] = (pScrn->videoRam - 64) / 32;
	  if(pSiS->Chipset != PCI_CHIP_SIS530) {	/* 530/620: Reserved (don't touch) */
    	     pReg->sisRegs3C4[0x3C] &= 0xFC; 		/* 6326: Queue is all for 2D */
	  }						/* 5597: Must be 0           */
       } else {
	  pReg->sisRegs3C4[0x27] &= 0x7F;
       }
    }


    if(!pSiS->UseVESA) {

       /* TW: No idea what this does. The Windows driver does it, so we do it as well */
       if(pSiS->Chipset == PCI_CHIP_SIS6326) {
          if((pSiS->ChipRev == 0xd0) || (pSiS->ChipRev == 0xd1) ||
             (pSiS->ChipRev == 0xd2) || (pSiS->ChipRev == 0x92) ||
	     (pSiS->Flags & A6326REVAB)) {
	     if((pSiS->Flags & (SYNCDRAM | RAMFLAG)) == (SYNCDRAM | RAMFLAG)) {
	        if(!(pReg->sisRegs3C4[0x0E] & 0x03)) {
	           pReg->sisRegs3C4[0x3E] |= 0x02;
	        }
	     }
          }
       }

       /* Set memclock */
#if 0
       /* We don't need to do this; the SetMClk option was not used since 4.0. */
       if((pSiS->Chipset == PCI_CHIP_SIS5597) || (pSiS->Chipset == PCI_CHIP_SIS6326)) {
          if(pSiS->MemClock > 66000) {
             SiSCalcClock(pScrn, pSiS->MemClock, 1, vclk);

             pReg->sisRegs3C4[0x28] = (vclk[Midx] - 1) & 0x7f ;
             pReg->sisRegs3C4[0x28] |= ((vclk[VLDidx] == 2 ) ? 1 : 0 ) << 7 ;
             pReg->sisRegs3C4[0x29] = (vclk[Nidx] -1) & 0x1f ;   /* bits [4:0] contain denumerator -MC */
             if(vclk[Pidx] <= 4) {
                pReg->sisRegs3C4[0x29] |= (vclk[Pidx] - 1) << 5 ; /* postscale 1,2,3,4 */
                pReg->sisRegs3C4[0x13] &= 0x7F;
             } else {
                pReg->sisRegs3C4[0x29] |= ((vclk[Pidx] / 2) - 1) << 5 ;  /* postscale 6,8 */
                pReg->sisRegs3C4[0x13] |= 0x80;
             }
             /* Check programmed memory clock. Enable only to check the above code */
/*
             mclk = 14318 * ((pReg->sisRegs3C4[0x28] & 0x7f) + 1);
             mclk /= ((pReg->sisRegs3C4[0x29] & 0x0f) + 1);
             if(!(pReg->sisRegs3C4[0x13] & 0x80)) {
                mclk /= (((pReg->sisRegs3C4[0x29] & 0x60) >> 5) + 1);
             } else {
                if((pReg->sisRegs3C4[0x29] & 0x60) == 0x40) mclk /= 6;
                if((pReg->sisRegs3C4[0x29] & 0x60) == 0x60) mclk /= 8;
             }
             xf86DrvMsgVerb(pScrn->scrnIndex, X_INFO,2,
                 "Setting memory clock to %.3f MHz\n",
                 mclk/1000.0);
*/
          }
       }
#endif

       /* Set threshold values */
       /*
        * CPU/CRT Threshold:                     FIFO
        *                           MCLK     ___________      VCLK
        * cpu/engine <---o       o--------->|___________| -----------> CRT
        *                ^       ^            ^       ^
        *                 \     /             |       |
        *                  \   /              |< gap >|
        *                   \ /               |       |
        *           selector switch   Thrsh. low     high
        *
        * CRT consumes the data in the FIFO during scanline display. When the
        * amount of data in the FIFO reaches the Threshold low value, the selector
        * switch will switch to the right, and the FIFO will be refilled with data.
        * When the amount of data in the FIFO reaches the Threshold high value, the
        * selector switch will switch to the left and allows the CPU and the chip
        * engines to access the video RAM.
        *
        * The Threshold low values should be increased at higher bpps, simply because
        * there is more data needed for the CRT. When Threshold low and high are very
        * close to each other, the selector switch will be activated more often, which
        * decreases performance.
        *
        */
       switch(pSiS->Chipset) {
       case PCI_CHIP_SIS5597:  factor = 65; break;
       case PCI_CHIP_SIS6326:  factor = 30; break;
       case PCI_CHIP_SIS530:   factor = (pSiS->Flags & UMA) ? 60 : 30; break;
       default:                factor = (pScrn->videoRam > 1024) ? 24 : 12;
       }
       a = width * height * rate * 1.40 * factor * ((pSiS->CurrentLayout.bitsPerPixel + 1) / 8);
       b = (mclk / 1000) * 999488.0 * (buswidth / 8);
       c = ((a / b) + 1.0) / 2;
       d = (int)c + 2;

#ifdef TWDEBUG
       xf86DrvMsg(0, X_INFO,
          "Debug: w %d h %d r %d mclk %d bus %d factor %d bpp %d\n",
          width, height, rate, mclk/1000, buswidth, factor,
          pSiS->CurrentLayout.bitsPerPixel);
       xf86DrvMsg(0, X_INFO, "Debug: a %f b %f c %f d %d (flags %x)\n",
     	  a, b, c, d, pSiS->Flags);
#endif

       CRT_CPUthresholdLow = d;
       if((pSiS->Flags & (RAMFLAG | SYNCDRAM)) == (RAMFLAG | SYNCDRAM)) {
          CRT_CPUthresholdLow += 2;
       }
       CRT_CPUthresholdHigh = CRT_CPUthresholdLow + 3;

       CRT_ENGthreshold = 0x0F;

#ifdef TWDEBUG
       xf86DrvMsg(0, X_INFO, "Debug: Thlow %d thhigh %d\n",
     	  CRT_CPUthresholdLow, CRT_CPUthresholdHigh);
#endif

#if 0  /* See comment in sis_dac.c on why this is commented */
       if(pSiS->Chipset == PCI_CHIP_SIS530) {
          if((pSiS->oldChipset == OC_SIS530A) &&
	     (pSiS->Flags & UMA) &&
	     (mclk == 100000) &&
	     (pSiS->Flags & ESS137xPRESENT)) {
	       if(!(pSiS->Flags & SECRETFLAG)) index = 0;
               if((temp = SiS_CalcSpecial530Threshold(pSiS, mode, index)) {
	    	   CRT_CPUthresholdLow = temp;
	           break;
	       }
          }
       }
#endif

       switch(pSiS->Chipset) {
       case PCI_CHIP_SIS530:
          if(CRT_CPUthresholdLow > 0x1f)  CRT_CPUthresholdLow = 0x1f;
          CRT_CPUthresholdHigh = 0x1f;
          break;
       case PCI_CHIP_SIS5597:
       case PCI_CHIP_SIS6326:
       default:
          if(CRT_CPUthresholdLow > 0x0f)  CRT_CPUthresholdLow  = 0x0f;
          if(CRT_CPUthresholdHigh > 0x0f) CRT_CPUthresholdHigh = 0x0f;
       }

       pReg->sisRegs3C4[0x08] = ((CRT_CPUthresholdLow & 0x0F) << 4) |
	  		        (CRT_ENGthreshold & 0x0F);

       pReg->sisRegs3C4[0x09] &= 0xF0;
       pReg->sisRegs3C4[0x09] |= (CRT_CPUthresholdHigh & 0x0F);

       pReg->sisRegs3C4[0x3F] &= 0xEB;
       pReg->sisRegs3C4[0x3F] |= (CRT_CPUthresholdHigh & 0x10) |
                         	      ((CRT_CPUthresholdLow & 0x10) >> 2);

       if(pSiS->oldChipset >= OC_SIS530A) {
     	  pReg->sisRegs3C4[0x3F] &= 0xDF;
	  pReg->sisRegs3C4[0x3F] |= 0x58;
       }

       /* Set SiS6326 TV registers */
       if((pSiS->Chipset == PCI_CHIP_SIS6326) && (sis6326tvmode)) {
          unsigned char tmp;
          int index=0, i, j, k;
          int fsc;

          if(pSiS->SiS6326Flags & SIS6326_TVPAL) {
             pReg->sisRegs3C4[0x0D] |= 0x04;
             switch(width) {
	     case 800:
	        if((strcmp(mode->name, "PAL800x600U") == 0))  index = 4;
	        else	        			      index = 3;
	        break;
	     case 720: index = 5;  break;
	     case 640:
	     default:  index = 2;
	     }
	     for(i=0; i<14; i++) {
	        pReg->sis6326tv[SiS6326TVRegs1[i]] = SiS6326TVRegs1_PAL[index][i];
	     }
             fsc = (SiS6326TVRegs1_PAL[index][2] << 16) |
	           (SiS6326TVRegs1_PAL[index][3] << 8)  |
	           (SiS6326TVRegs1_PAL[index][4]);
          } else {
	     pReg->sisRegs3C4[0x0D] &= ~0x04;
	     if((strcmp(mode->name, "NTSC640x480U") == 0))  index = 5;
	     else 					    index = 4;
             for(i=0; i<14; i++) {
	        pReg->sis6326tv[SiS6326TVRegs1[i]] = SiS6326TVRegs1_NTSC[index][i];
	     }
             fsc = (SiS6326TVRegs1_NTSC[index][2] << 16) |
	           (SiS6326TVRegs1_NTSC[index][3] << 8)  |
	           (SiS6326TVRegs1_NTSC[index][4]);
          }
          if(pSiS->sis6326fscadjust) {
	     fsc += pSiS->sis6326fscadjust;
	     pReg->sis6326tv[2] = (fsc >> 16) & 0xff;
	     pReg->sis6326tv[3] = (fsc >> 8) & 0xff;
	     pReg->sis6326tv[4] = fsc & 0xff;
          }
          tmp = pReg->sis6326tv[0x43];
          if(pSiS->SiS6326Flags & SIS6326_TVCVBS) tmp |= 0x10;
          tmp |= 0x08;
          pReg->sis6326tv[0x43] = tmp;
          j = 0; k = 0;
          for(i=0; i<=0x44; i++) {
	     if(SiS6326TVRegs1[j] == i) {
	 	j++;
		continue;
	     }
	     if(pSiS->SiS6326Flags & SIS6326_TVPAL) {
		tmp = SiS6326TVRegs2_PAL[index][k];
	     } else {
		tmp = SiS6326TVRegs2_NTSC[index][k];
	     }
	     pReg->sis6326tv[i] = tmp;
	     k++;
          }
          pReg->sis6326tv[0x43] |= 0x08;
          if((pSiS->ChipRev == 0xc1) || (pSiS->ChipRev == 0xc2)) {
             pReg->sis6326tv[0x43] &= ~0x08;
          }

          tmp = pReg->sis6326tv[0];
          tmp |= 0x18;
          if(pSiS->SiS6326Flags & SIS6326_TVCVBS)   tmp &= ~0x10;
          if(pSiS->SiS6326Flags & SIS6326_TVSVIDEO) tmp &= ~0x08;
          tmp |= 0x04;
          pReg->sis6326tv[0] = tmp;
       }

    } /* VESA */

    return(TRUE);
}

/* Init a mode for SiS 300, 315 and 330 series
 * This function is now only used for setting up some
 * variables (eg. scrnOffset).
 */
Bool
SIS300Init(ScrnInfoPtr pScrn, DisplayModePtr mode)
{
    SISPtr         pSiS = SISPTR(pScrn);
    SISRegPtr      pReg = &pSiS->ModeReg;
    unsigned short temp;
    DisplayModePtr realmode = mode;

    PDEBUG(xf86DrvMsgVerb(pScrn->scrnIndex, X_INFO, 4, "SIS300Init()\n"));

    xf86DrvMsgVerb(pScrn->scrnIndex, X_INFO, 4,
        "virtualX = %d depth = %d Logical width = %d\n",
	pScrn->virtualX, pSiS->CurrentLayout.bitsPerPixel,
        pScrn->virtualX * pSiS->CurrentLayout.bitsPerPixel/8);

#ifdef SISMERGED
    if(pSiS->MergedFB) {
       realmode = ((SiSMergedDisplayModePtr)mode->Private)->CRT1;
    }
#endif

    /* Copy current register settings to structure */
    (*pSiS->SiSSave)(pScrn, pReg);

    /* Calculate Offset/Display Pitch */
    pSiS->scrnOffset = pSiS->CurrentLayout.displayWidth *
                          ((pSiS->CurrentLayout.bitsPerPixel + 7) / 8);

    pSiS->scrnPitch = pSiS->scrnPitch2 = pSiS->scrnOffset;
    if(!(pSiS->VBFlags & CRT1_LCDA)) {
       if(realmode->Flags & V_INTERLACE) pSiS->scrnPitch <<= 1;
    }
    /* CRT2 mode can never be interlaced */

#ifdef UNLOCK_ALWAYS
    outSISIDXREG(SISSR, 0x05, 0x86);
#endif

    switch(pSiS->CurrentLayout.bitsPerPixel) {
        case 8:
            pSiS->DstColor = 0x0000;
	    pSiS->SiS310_AccelDepth = 0x00000000;
            break;
        case 16:
	    if(pSiS->CurrentLayout.depth == 15)
	        pSiS->DstColor = (short) 0x4000;
	    else
                pSiS->DstColor = (short) 0x8000;
	    pSiS->SiS310_AccelDepth = 0x00010000;
            break;
        case 24:
            break;
        case 32:
            pSiS->DstColor = (short) 0xC000;
	    pSiS->SiS310_AccelDepth = 0x00020000;
            break;
    }

    /* Enable PCI LINEAR ADDRESSING (0x80), MMIO (0x01), PCI_IO (0x20) */
    pReg->sisRegs3C4[0x20] = 0xA1;

    /* Now initialize TurboQueue. TB is always located at the very top of
     * the videoRAM (notably NOT the x framebuffer memory, which can/should
     * be limited by MaxXFbMem when using DRI). Also, enable the accelerators.
     */
    if(!pSiS->NoAccel) {
        pReg->sisRegs3C4[0x1E] |= 0x42;  /* Enable 2D accelerator */
	pReg->sisRegs3C4[0x1E] |= 0x18;  /* Enable 3D accelerator */
	switch(pSiS->VGAEngine) {
	case SIS_300_VGA:
	  if(pSiS->TurboQueue) {    		/* set Turbo Queue as 512k */
	    temp = ((pScrn->videoRam/64)-8);    /* 8=512k, 4=256k, 2=128k, 1=64k */
            pReg->sisRegs3C4[0x26] = temp & 0xFF;
	    pReg->sisRegs3C4[0x27] =
		(pReg->sisRegs3C4[0x27] & 0xfc) | (((temp >> 8) & 3) | 0xF0);
          }	/* line above new for saving D2&3 of status register */
	  break;
	case SIS_315_VGA:
#ifndef SISVRAMQ
	  /* See comments in sis_driver.c */
	  pReg->sisRegs3C4[0x27] = 0x1F;
	  pReg->sisRegs3C4[0x26] = 0x22;
	  pReg->sisMMIO85C0 = (pScrn->videoRam - 512) * 1024;
#endif
	  break;
	}
    }

    return(TRUE);
}

static int
SISDoSense(ScrnInfoPtr pScrn, unsigned short type, unsigned short test)
{
    SISPtr pSiS = SISPTR(pScrn);
    int    temp, mytest, result, i, j;

#ifdef TWDEBUG
    xf86DrvMsg(0, X_INFO, "Sense: %x %x\n", type, test);
#endif

    for(j = 0; j < 10; j++) {
       result = 0;
       for(i = 0; i < 3; i++) {
          mytest = test;
          outSISIDXREG(SISPART4,0x11,(type & 0x00ff));
          temp = (type >> 8) | (mytest & 0x00ff);
          setSISIDXREG(SISPART4,0x10,0xe0,temp);
          SiS_DDC2Delay(pSiS->SiS_Pr, 0x1500);
          mytest >>= 8;
          mytest &= 0x7f;
          inSISIDXREG(SISPART4,0x03,temp);
          temp ^= 0x0e;
          temp &= mytest;
          if(temp == mytest) result++;
#if 1
	  outSISIDXREG(SISPART4,0x11,0x00);
	  andSISIDXREG(SISPART4,0x10,0xe0);
	  SiS_DDC2Delay(pSiS->SiS_Pr, 0x1000);
#endif
       }
       if((result == 0) || (result >= 2)) break;
    }
    return(result);
}

#define GETROMWORD(w) (pSiS->BIOS[w] | (pSiS->BIOS[w+1] << 8))

/* Sense connected devices on 30x */
static void
SISSense30x(ScrnInfoPtr pScrn)
{
    SISPtr  pSiS = SISPTR(pScrn);
    unsigned char backupP4_0d,backupP2_00,backupP2_4d,biosflag=0;
    unsigned short svhs=0, svhs_c=0;
    unsigned short cvbs=0, cvbs_c=0;
    unsigned short vga2=0, vga2_c=0;
    int myflag, result; /* , i; */

    inSISIDXREG(SISPART4,0x0d,backupP4_0d);
    outSISIDXREG(SISPART4,0x0d,(backupP4_0d | 0x04));
    SiS_DDC2Delay(pSiS->SiS_Pr, 0x2000);

    inSISIDXREG(SISPART2,0x00,backupP2_00);
    outSISIDXREG(SISPART2,0x00,((backupP2_00 | 0x1c) & 0xfc));

    inSISIDXREG(SISPART2,0x4d,backupP2_4d);
    if(pSiS->VBFlags & (VB_301C|VB_301LV|VB_302LV|VB_302ELV)) {
       outSISIDXREG(SISPART2,0x4d,(backupP2_4d & ~0x10));
    }

    SISDoSense(pScrn, 0, 0);

    if(pSiS->VBFlags & VB_301) {
       svhs = 0x00b9; cvbs = 0x00b3; vga2 = 0x00d1;
       inSISIDXREG(SISPART4,0x01,myflag);
       if(myflag & 0x04) {
	  svhs = 0x00dd; cvbs = 0x00ee; vga2 = 0x00fd;
       }
    } else if(pSiS->VBFlags & (VB_301B | VB_302B)) {
       svhs = 0x016b; cvbs = 0x0174; vga2 = 0x0190;
    } else if(pSiS->VBFlags & (VB_301LV | VB_302LV)) {
       svhs = 0x0200; cvbs = 0x0100;
    } else if(pSiS->VBFlags & (VB_301C | VB_302ELV)) {
       svhs = 0x016b; cvbs = 0x0110; vga2 = 0x0190;
    } else return;

    vga2_c = 0x0e08; svhs_c = 0x0404; cvbs_c = 0x0804;
    if(pSiS->VBFlags & (VB_301LV|VB_302LV|VB_302ELV)) {
       svhs_c = 0x0408; cvbs_c = 0x0808;
    }
    biosflag = 2;

    if(pSiS->Chipset == PCI_CHIP_SIS300) {
       inSISIDXREG(SISSR,0x3b,myflag);
       if(!(myflag & 0x01)) vga2 = vga2_c = 0;
    }

    if(pSiS->sishw_ext.UseROM) {
       if(pSiS->VGAEngine == SIS_300_VGA) {
          if(pSiS->VBFlags & VB_301) {
	     inSISIDXREG(SISPART4,0x01,myflag);
             if(!(myflag & 0x04)) {
                vga2 = GETROMWORD(0xf8); svhs = GETROMWORD(0xfa); cvbs = GETROMWORD(0xfc);
	     }
	  }
	  biosflag = pSiS->BIOS[0xfe];
       } else if(pSiS->Chipset == PCI_CHIP_SIS660) {
          if(pSiS->ROM661New) {
	     biosflag = 2;
	     vga2 = GETROMWORD(0x63); svhs = cvbs = GETROMWORD(0x65);
	     if(pSiS->BIOS[0x5d] & 0x04) biosflag |= 0x01;
	  }
       } else if(!pSiS->ROM661New) {
#if 0	  /* eg. 1.15.23 has wrong values here */
          myflag = 0;
          if(pSiS->VBFlags & VB_301) {
	     if(pSiS->Chipset == PCI_CHIP_SIS330) {
	        myflag = 0xe5; i = 0x11b;
	     } else {
	        myflag = 0xbd; i = 0xf3
	     }
	  } else if(pSiS->VBFlags & (VB_301B|VB_302B|VB_301LV|VB_302LV)) {
	     if(pSiS->Chipset == PCI_CHIP_SIS330) {
	        myflag = 0xeb; i = 0x11b;
	     } else {
	        myflag = 0xc3; i = 0xf3
	     }
	  }
	  if(myflag) {
	     biosflag = pSiS->BIOS[i];    vga2 = GETROMWORD(myflag);
	     svhs = GETROMWORD(myflag+2); cvbs = GETROMWORD(myflag+4);
	  }
#endif
       }
    }

    if(pSiS->VBFlags & (VB_301LV|VB_302LV|VB_302ELV)) {
       vga2 = vga2_c = 0;
    }

    andSISIDXREG(SISCR, 0x32, ~0x14);
    pSiS->postVBCR32 &= ~0x14;
    
    if(vga2_c || vga2) {
       if(SISDoSense(pScrn, vga2, vga2_c)) {
          if(biosflag & 0x01) {
	     xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
	         "SiS30x: Detected TV connected to SCART output\n");
	     pSiS->VBFlags |= TV_SCART;
	     orSISIDXREG(SISCR, 0x32, 0x04);
	     pSiS->postVBCR32 |= 0x04;
	  } else {
	     xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
	         "SiS30x: Detected secondary VGA connection\n");
	     pSiS->VBFlags |= VGA2_CONNECTED;
	     orSISIDXREG(SISCR, 0x32, 0x10);
	     pSiS->postVBCR32 |= 0x10;
	  }
       }
       if(biosflag & 0x01) pSiS->SiS_SD_Flags |= SiS_SD_VBHASSCART;
    }

    andSISIDXREG(SISCR, 0x32, 0x3f);
    pSiS->postVBCR32 &= 0x3f;

    if((pSiS->VGAEngine == SIS_315_VGA) && (pSiS->VBFlags & (VB_301C|VB_301LV|VB_302LV|VB_302ELV))) {
       if(pSiS->SenseYPbPr) {
          outSISIDXREG(SISPART2,0x4d,(backupP2_4d | 0x10));
          SiS_DDC2Delay(pSiS->SiS_Pr, 0x2000);
          if((result = SISDoSense(pScrn, svhs, 0x0604))) {
             if((result = SISDoSense(pScrn, cvbs, 0x0804))) {
	        xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
     			"SiS30x: Detected TV connected to YPbPr component output\n");
	        orSISIDXREG(SISCR,0x32,0x80);
	        pSiS->VBFlags |= TV_YPBPR;
	        pSiS->postVBCR32 |= 0x80;
	     }
          }
          outSISIDXREG(SISPART2,0x4d,backupP2_4d);
       }
    }

    andSISIDXREG(SISCR, 0x32, ~0x03);
    pSiS->postVBCR32 &= ~0x03;

    if(!(pSiS->VBFlags & TV_YPBPR)) {

       if((result = SISDoSense(pScrn, svhs, svhs_c))) {
          xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
     		"SiS30x: Detected TV connected to SVIDEO output\n");
          pSiS->VBFlags |= TV_SVIDEO;
          orSISIDXREG(SISCR, 0x32, 0x02);
          pSiS->postVBCR32 |= 0x02;
       }

       if((biosflag & 0x02) || (!result)) {
          if(SISDoSense(pScrn, cvbs, cvbs_c)) {
	     xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
	             "SiS30x: Detected TV connected to COMPOSITE output\n");
	     pSiS->VBFlags |= TV_AVIDEO;
	     orSISIDXREG(SISCR, 0x32, 0x01);
	     pSiS->postVBCR32 |= 0x01;
          }
       }

    }

    SISDoSense(pScrn, 0, 0);

    outSISIDXREG(SISPART2,0x00,backupP2_00);
    outSISIDXREG(SISPART4,0x0d,backupP4_0d);
}

static void
SiS6326TVDelay(ScrnInfoPtr pScrn, int delay)
{
    SISPtr  pSiS = SISPTR(pScrn);
    int i;
    unsigned char temp;

    for(i=0; i<delay; i++) {
    	inSISIDXREG(SISSR, 0x05, temp);
    }
    (void)temp;
}

static int
SIS6326DoSense(ScrnInfoPtr pScrn, int tempbh, int tempbl, int tempch, int tempcl)
{
    unsigned char temp;

    SiS6326SetTVReg(pScrn, 0x42, tempbl);
    temp = SiS6326GetTVReg(pScrn, 0x43);
    temp &= 0xfc;
    temp |= tempbh;
    SiS6326SetTVReg(pScrn, 0x43, temp);
    SiS6326TVDelay(pScrn, 0x1000);
    temp = SiS6326GetTVReg(pScrn, 0x43);
    temp |= 0x04;
    SiS6326SetTVReg(pScrn, 0x43, temp);
    SiS6326TVDelay(pScrn, 0x8000);
    temp = SiS6326GetTVReg(pScrn, 0x44);
    if(!(tempch & temp)) tempcl = 0;
    return(tempcl);
}

static void
SISSense6326(ScrnInfoPtr pScrn)
{
    SISPtr pSiS = SISPTR(pScrn);
    unsigned char temp;
    int result;

    pSiS->SiS6326Flags &= (SIS6326_HASTV | SIS6326_TVPAL);
    temp = SiS6326GetTVReg(pScrn, 0x43);
    temp &= 0xfb;
    SiS6326SetTVReg(pScrn, 0x43, temp);
    result = SIS6326DoSense(pScrn, 0x01, 0xb0, 0x06, SIS6326_TVSVIDEO);  /* 0x02 */
    pSiS->SiS6326Flags |= result;
    result = SIS6326DoSense(pScrn, 0x01, 0xa0, 0x01, SIS6326_TVCVBS);    /* 0x04 */
    pSiS->SiS6326Flags |= result;
    temp = SiS6326GetTVReg(pScrn, 0x43);
    temp &= 0xfb;
    SiS6326SetTVReg(pScrn, 0x43, temp);
    if(pSiS->SiS6326Flags & (SIS6326_TVSVIDEO | SIS6326_TVCVBS)) {
    	pSiS->SiS6326Flags |= SIS6326_TVDETECTED;
	xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
		"SiS6326: Detected TV connected to %s output\n",
		(((pSiS->SiS6326Flags & (SIS6326_TVSVIDEO | SIS6326_TVCVBS)) ==
		   (SIS6326_TVSVIDEO | SIS6326_TVCVBS)) ?
		   	"both SVIDEO and COMPOSITE" :
		      	   ((pSiS->SiS6326Flags & SIS6326_TVSVIDEO) ?
			     	"SVIDEO" : "COMPOSITE")));
    } else {
        xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
		"SiS6326: No TV detected\n");
    }
}

/* Detect video bridge and set VBFlags accordingly */
void SISVGAPreInit(ScrnInfoPtr pScrn)
{
    SISPtr  pSiS = SISPTR(pScrn);
    int     temp,temp1,temp2, i;
    int     upperlimitlvds, lowerlimitlvds;
    int     upperlimitch, lowerlimitch;
    int     chronteltype, chrontelidreg, upperlimitvb;
    unsigned char test[3];
    static const char *detectvb = "Detected %s video bridge (ID %d; Revision 0x%x)\n";
#if 0
    unsigned char sr17=0;
#endif
    static const char  *ChrontelTypeStr[] = {
        "7004",
	"7005",
	"7007",
	"7006",
	"7008",
	"7013",
	"7019",
	"7020",
	"(unknown)"
    };

    switch (pSiS->Chipset) {
        case PCI_CHIP_SIS300:
        case PCI_CHIP_SIS630:
        case PCI_CHIP_SIS540:
	case PCI_CHIP_SIS550:
	case PCI_CHIP_SIS650:
	case PCI_CHIP_SIS315:
	case PCI_CHIP_SIS315H:
	case PCI_CHIP_SIS315PRO:
	case PCI_CHIP_SIS330:
	case PCI_CHIP_SIS660:
            pSiS->ModeInit = SIS300Init;
            break;
        default:
            pSiS->ModeInit = SISInit;
    }

    if((pSiS->Chipset == PCI_CHIP_SIS6326) && (pSiS->SiS6326Flags & SIS6326_HASTV)) {
        unsigned char sr0d;
	inSISIDXREG(SISSR, 0x0d, sr0d);
	if(sr0d & 0x04) {
		pSiS->SiS6326Flags |= SIS6326_TVPAL;
	}
	SISSense6326(pScrn);
    }

    pSiS->VBFlags = 0; /* reset VBFlags */
    pSiS->SiS_Pr->SiS_UseLCDA = FALSE;
    pSiS->SiS_Pr->Backup = FALSE;

    /* Videobridges only available for 300/315 series */
    if((pSiS->VGAEngine != SIS_300_VGA) && (pSiS->VGAEngine != SIS_315_VGA))
        return;
	
    inSISIDXREG(SISPART4, 0x00, temp);
    temp &= 0x0F;
    if(temp == 1) {
        inSISIDXREG(SISPART4, 0x01, temp1);
	temp1 &= 0xff;
        if(temp1 >= 0xE0) {
	        inSISIDXREG(SISPART4, 0x39, temp2);
		if(temp2 == 0xff) {
	   	   pSiS->VBFlags |= VB_302LV;
		   pSiS->sishw_ext.ujVBChipID = VB_CHIP_302LV;
    		   xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb, "SiS302LV", 1, temp1);
		} else {
		   pSiS->VBFlags |= VB_302ELV;
		   pSiS->sishw_ext.ujVBChipID = VB_CHIP_302ELV;
    		   xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb, "SiS302ELV", 1, temp1);
		}
	} else if(temp1 >= 0xD0) {
	   	pSiS->VBFlags |= VB_301LV;
		pSiS->sishw_ext.ujVBChipID = VB_CHIP_301LV;
    		xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb, "SiS301LV", 1, temp1);
	} else if(temp1 >= 0xC0) {
	   	pSiS->VBFlags |= VB_301C;
		pSiS->sishw_ext.ujVBChipID = VB_CHIP_301C;
    		xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb, "SiS301C", 1, temp1);
	} else if(temp1 >= 0xB0) {
	        pSiS->VBFlags |= VB_301B;
		pSiS->sishw_ext.ujVBChipID = VB_CHIP_301B;
		inSISIDXREG(SISPART4, 0x23, temp2);
		if(!(temp2 & 0x02)) pSiS->VBFlags |= VB_30xBDH;
    		xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb,
				(temp2 & 0x02) ? "SiS301B" : "SiS301B-DH", 1, temp1);
	} else {
	        pSiS->VBFlags |= VB_301;
		pSiS->sishw_ext.ujVBChipID = VB_CHIP_301;
		xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb, "SiS301", 1, temp1);
	}

	SISSense30x(pScrn); 

    } else if (temp == 2) {

        inSISIDXREG(SISPART4, 0x01, temp1);
	temp1 &= 0xff;
	if(temp1 >= 0xE0) {
        	pSiS->VBFlags |= VB_302LV;
		pSiS->sishw_ext.ujVBChipID = VB_CHIP_302LV;
    		xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb, "SiS302LV", 2, temp1);
	} else if(temp1 >= 0xD0) {
        	pSiS->VBFlags |= VB_301LV;
		pSiS->sishw_ext.ujVBChipID = VB_CHIP_301LV;
    		xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb, "SiS301LV", 2, temp1);
	} else {
	        pSiS->VBFlags |= VB_302B;
		pSiS->sishw_ext.ujVBChipID = VB_CHIP_302B;
		inSISIDXREG(SISPART4, 0x23, temp2);
		if(!(temp & 0x02)) pSiS->VBFlags |= VB_30xBDH;
    		xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb,
				(temp2 & 0x02) ? "SiS302B" : "SiS302B-DH", 2, temp1);
	}

	SISSense30x(pScrn);

    } else if (temp == 3) {

    	xf86DrvMsg(pScrn->scrnIndex, X_PROBED, detectvb, "unsupported SiS303", temp, 0);

    } else {

        pSiS->sishw_ext.ujVBChipID = VB_CHIP_UNKNOWN;
	if(pSiS->Chipset == PCI_CHIP_SIS660) {
	   inSISIDXREG(SISCR, 0x38, temp);
           temp = (temp >> 5) & 0x07;
	} else {
	   inSISIDXREG(SISCR, 0x37, temp);
           temp = (temp >> 1) & 0x07;
	}
        if(pSiS->VGAEngine == SIS_300_VGA) {
	   lowerlimitlvds = 2; upperlimitlvds = 4;
	   lowerlimitch   = 4; upperlimitch   = 5;
	   chronteltype = 1;   chrontelidreg  = 0x25;
	   upperlimitvb = upperlimitlvds;
        } else {
	   lowerlimitlvds = 2; upperlimitlvds = 3;
	   lowerlimitch   = 3; upperlimitch   = 3;
	   chronteltype = 2;   chrontelidreg  = 0x4b;
	   upperlimitvb = upperlimitlvds;
	   if(pSiS->Chipset == PCI_CHIP_SIS660) {
	      upperlimitvb = 4;
	   }
	}

	if((temp >= lowerlimitlvds) && (temp <= upperlimitlvds)) {
               pSiS->VBFlags |= VB_LVDS;
    	       xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
	               "Detected LVDS transmitter (External chip ID %d)\n", temp);
	}
        if((temp >= lowerlimitch) && (temp <= upperlimitch))  {
	    /* Set global for init301.c */
	    pSiS->SiS_Pr->SiS_IF_DEF_CH70xx = chronteltype;

	    if(chronteltype == 1) {
	       /* Set general purpose IO for Chrontel communication */
	       SiS_SetChrontelGPIO(pSiS->SiS_Pr, 0x9c);
	    }

	    /* Read Chrontel version number */
 	    temp1 = SiS_GetCH70xx(pSiS->SiS_Pr, chrontelidreg);
	    if(chronteltype == 1) {
	        /* See Chrontel TB31 for explanation */
		temp2 = SiS_GetCH700x(pSiS->SiS_Pr, 0x0e);
		if(((temp2 & 0x07) == 0x01) || (temp2 & 0x04)) {
		    SiS_SetCH700x(pSiS->SiS_Pr, 0x0b0e);
		    SiS_DDC2Delay(pSiS->SiS_Pr, 300);
		}
	        temp2 = SiS_GetCH70xx(pSiS->SiS_Pr, chrontelidreg);
		if(temp2 != temp1) temp1 = temp2;
	    }
	    if(temp1 == 0xFFFF) {	/* 0xFFFF = error reading DDC port */
	    	xf86DrvMsg(pScrn->scrnIndex, X_ERROR,
			"Detected Chrontel 70xx, but encountered error reading I2C port\n");
		andSISIDXREG(SISCR, 0x32, ~0x07);
		pSiS->postVBCR32 &= ~0x07;
	    }
	    /* TW: We only support device ids 0x19-200; other values may indicate DDC problems */
	    else if((temp1 >= 0x19) && (temp1 <= 200)) {
	        pSiS->VBFlags |= VB_CHRONTEL;
		switch (temp1) {
		   case 0x32: temp2 = 0; pSiS->ChrontelType = CHRONTEL_700x; break;
		   case 0x3A: temp2 = 1; pSiS->ChrontelType = CHRONTEL_700x; break;
		   case 0x50: temp2 = 2; pSiS->ChrontelType = CHRONTEL_700x; break;
		   case 0x2A: temp2 = 3; pSiS->ChrontelType = CHRONTEL_700x; break;
		   case 0x40: temp2 = 4; pSiS->ChrontelType = CHRONTEL_700x; break;
		   case 0x22: temp2 = 5; pSiS->ChrontelType = CHRONTEL_700x; break;
	           case 0x19: temp2 = 6; pSiS->ChrontelType = CHRONTEL_701x; break;
	           case 0x20: temp2 = 7; pSiS->ChrontelType = CHRONTEL_701x; break;  /* ID for 7020? */
		   default:   temp2 = 8; pSiS->ChrontelType = CHRONTEL_701x; break;
		}
   	        xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
	               "Detected Chrontel %s TV encoder (ID 0x%02x; chip ID %d)\n",
		       			ChrontelTypeStr[temp2], temp1, temp);

		/* Sense connected TV's */

		if(chronteltype == 1) {

		   /* Chrontel 700x */

	    	   /* Read power status */
	    	   temp1 = SiS_GetCH700x(pSiS->SiS_Pr, 0x0e);  /* Power status */
	    	   if((temp1 & 0x03) != 0x03) {
		        /* TW: Power all outputs */
	        	SiS_SetCH700x(pSiS->SiS_Pr, 0x0B0E);
			SiS_DDC2Delay(pSiS->SiS_Pr, 0x96);
	    	   }
		   /* Sense connected TV devices */
		   for(i = 0; i < 3; i++) {
	    	      SiS_SetCH700x(pSiS->SiS_Pr, 0x0110);
		      SiS_DDC2Delay(pSiS->SiS_Pr, 0x96);
	    	      SiS_SetCH700x(pSiS->SiS_Pr, 0x0010);
		      SiS_DDC2Delay(pSiS->SiS_Pr, 0x96);
	    	      temp1 = SiS_GetCH700x(pSiS->SiS_Pr, 0x10);
		      if(!(temp1 & 0x08))       test[i] = 0x02;
		      else if(!(temp1 & 0x02))  test[i] = 0x01;
		      else                      test[i] = 0;
		      SiS_DDC2Delay(pSiS->SiS_Pr, 0x96);
		   }

		   if(test[0] == test[1])      temp1 = test[0];
		   else if(test[0] == test[2]) temp1 = test[0];
		   else if(test[1] == test[2]) temp1 = test[1];
		   else {
		   	xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
				"TV detection unreliable - test results varied\n");
			temp1 = test[2];
		   }

		} else {

		   /* Chrontel 701x */

		   /* Backup Power register */
		   temp1 = SiS_GetCH701x(pSiS->SiS_Pr, 0x49);

		   /* Enable TV path */
		   SiS_SetCH701x(pSiS->SiS_Pr, 0x2049);

		   SiS_DDC2Delay(pSiS->SiS_Pr, 0x96);

		   /* Sense connected TV devices */
		   temp2 = SiS_GetCH701x(pSiS->SiS_Pr, 0x20);
		   temp2 |= 0x01;
		   SiS_SetCH701x(pSiS->SiS_Pr, (temp2 << 8) | 0x20);

		   SiS_DDC2Delay(pSiS->SiS_Pr, 0x96);

		   temp2 ^= 0x01;
		   SiS_SetCH701x(pSiS->SiS_Pr, (temp2 << 8) | 0x20);

		   SiS_DDC2Delay(pSiS->SiS_Pr, 0x96);

		   temp2 = SiS_GetCH701x(pSiS->SiS_Pr, 0x20); 

		   /* Restore Power register */
		   SiS_SetCH701x(pSiS->SiS_Pr, (temp1 << 8) | 0x49);

                   temp1 = 0;
		   if(temp2 & 0x02) temp1 |= 0x01;
		   if(temp2 & 0x10) temp1 |= 0x01;
		   if(temp2 & 0x04) temp1 |= 0x02;

		   if( (temp1 & 0x01) && (temp1 & 0x02) ) temp1 = 0x04;

                }

		switch(temp1) {
		     case 0x01:
		        xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
		  	   "Chrontel: Detected TV connected to COMPOSITE output\n");
			pSiS->VBFlags |= TV_AVIDEO;
			orSISIDXREG(SISCR, 0x32, 0x01);
			andSISIDXREG(SISCR, 0x32, ~0x06);
			pSiS->postVBCR32 |= 0x01;
			pSiS->postVBCR32 &= ~0x06;
                        break;
                     case 0x02:
			xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
			   "Chrontel: Detected TV connected to SVIDEO output\n");
			pSiS->VBFlags |= TV_SVIDEO;
			orSISIDXREG(SISCR, 0x32, 0x02);
			andSISIDXREG(SISCR, 0x32, ~0x05);
			pSiS->postVBCR32 |= 0x02;
			pSiS->postVBCR32 &= ~0x05;
                        break;
		     case 0x04:
			xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
			   "Chrontel: Detected TV connected to SCART or YPBPR output\n");
			if(pSiS->chtvtype == -1) {
			   xf86DrvMsg(pScrn->scrnIndex, X_INFO,
			      "Chrontel: Use CHTVType option to select either SCART or YPBPR525I\n");
			   xf86DrvMsg(pScrn->scrnIndex, X_INFO,
			      "Chrontel: Using SCART by default\n");
			   pSiS->chtvtype = 1;
			}
			if(pSiS->chtvtype)
			    pSiS->VBFlags |= TV_CHSCART;
			else
			    pSiS->VBFlags |= TV_CHYPBPR525I;
                        break;
		     default:
		        xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
		  	   "Chrontel: No TV detected.\n");
			andSISIDXREG(SISCR, 0x32, ~0x07);
			pSiS->postVBCR32 &= ~0x07;
		}

	    } else if(temp1==0) {
	        /* This indicates a communication problem, but it only occures if there
		 * is no TV attached. So we don't use TV in this case.
		 */
	    	xf86DrvMsg(pScrn->scrnIndex, X_INFO,
			"Detected Chrontel TV encoder in promiscuous state (DDC/I2C mix-up)\n");
		andSISIDXREG(SISCR, 0x32, ~0x07);
		pSiS->postVBCR32 &= ~0x07;
	    } else {
	    	xf86DrvMsg(pScrn->scrnIndex, X_ERROR,
			"Chrontel: Unsupported device id (%d) detected\n",temp1);
		andSISIDXREG(SISCR, 0x32, ~0x07);
		pSiS->postVBCR32 &= ~0x07;
	    }
	    if(chronteltype == 1) {
	       /* Set general purpose IO for Chrontel communication */
	       SiS_SetChrontelGPIO(pSiS->SiS_Pr, 0x00);
	    }
	}
	if((pSiS->Chipset == PCI_CHIP_SIS660) && (temp == 4)) {
	   pSiS->VBFlags |= VB_CONEXANT;
	   xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
	               "Detected Conexant video bridge - UNSUPPORTED\n");
	}
	if((pSiS->VGAEngine == SIS_300_VGA) && (temp == 3)) {
	    pSiS->VBFlags |= VB_TRUMPION;
	    xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
	               "Detected Trumpion Zurac (I/II/III) LVDS scaler\n");
	}
	if(temp > upperlimitvb) {
	    xf86DrvMsg(pScrn->scrnIndex, X_ERROR,
	               "Detected unknown bridge type (%d)\n", temp);
	}
    }

   /* Old BIOSes store the detected CRT2 type in SR17, 16 and 13
    * instead of CR32. However, since our detection routines
    * store their results to CR32, we now copy the
    * remaining bits (for LCD and VGA) to CR32 for unified usage.
    * SR17[0] CRT1     [1] LCD       [2] TV    [3] VGA2
    *     [4] AVIDEO   [5] SVIDEO
    * SR13[0] SCART    [1] HiVision
    * SR16[5] PAL/NTSC [6] LCD-SCALE [7] OVERSCAN
    */

#if 0
    inSISIDXREG(SISSR, 0x17, sr17);
    if( (pSiS->VGAEngine == SIS_300_VGA) &&
        (pSiS->Chipset != PCI_CHIP_SIS300) &&
        (sr17 & 0x0F) ) {
	
	unsigned char cr32;
	inSISIDXREG(SISCR, 0x32, cr32);
	
	xf86DrvMsg(pScrn->scrnIndex, X_INFO, 
		"Converting SR17 (%02x) to CR32 (%02x)\n", sr17, cr32);
	 
	 if(sr17 & 0x01) {  	/* CRT1 */
	 	orSISIDXREG(SISCR, 0x32, 0x20);
		pSiS->postVBCR32 |= 0x20;
	 } else {
	 	andSISIDXREG(SISCR, 0x32, ~0x20);
		pSiS->postVBCR32 &= ~0x20;
	 }
		
	 if(sr17 & 0x02) {	/* LCD */
	 	orSISIDXREG(SISCR, 0x32, 0x08);
		pSiS->postVBCR32 |= 0x08;
	 } else	{	  
	 	andSISIDXREG(SISCR, 0x32, ~0x08);
		pSiS->postVBCR32 &= ~0x08;
	 }
	 
	 /* No Hivision, no DVI here */
	 andSISIDXREG(SISCR,0x32,~0xc0);
	 pSiS->postVBCR32 &= ~0xc0;
    }  
#endif

    /* Try to find out if the bridge uses LCDA for low resolution and
     * text modes. If sisfb saved this for us, use it. Otherwise,
     * check if we are running on a low mode on LCD and read the 
     * relevant registers ourselves.
     */
    if(pSiS->VGAEngine == SIS_315_VGA) {

       if(pSiS->VBFlags & (VB_301C | VB_302B | VB_301LV | VB_302LV | VB_302ELV)) {
          if(pSiS->sisfblcda != 0xff) {
	     if((pSiS->sisfblcda & 0x03) == 0x03) {
	        pSiS->SiS_Pr->SiS_UseLCDA = TRUE;
	        pSiS->ChipFlags |= SiSCF_UseLCDA;
	     }
	  } else {
             inSISIDXREG(SISCR,0x34,temp);
	     if(temp <= 0x13) {
	        inSISIDXREG(SISCR,0x38,temp);
	        if((temp & 0x03) == 0x03) {
	           pSiS->SiS_Pr->SiS_UseLCDA = TRUE;
	           pSiS->ChipFlags |= SiSCF_UseLCDA;
		   pSiS->SiS_Pr->Backup = TRUE;
	        } else {
		   orSISIDXREG(SISPART1,0x2f,0x01);  /* Unlock CRT2 */
		   inSISIDXREG(SISPART1,0x13,temp);
		   if(temp & 0x04) {
		      pSiS->SiS_Pr->SiS_UseLCDA = TRUE;
	              pSiS->ChipFlags |= SiSCF_UseLCDA;
		      pSiS->SiS_Pr->Backup = TRUE;
		   }
	        }
	     }
	  }
	  if(pSiS->ChipFlags & SiSCF_UseLCDA) {
	     xf86DrvMsg(pScrn->scrnIndex, X_PROBED,
		"BIOS uses LCDA for low resolution and text modes\n");
	     if(pSiS->SiS_Pr->Backup == TRUE) {
	        inSISIDXREG(SISCR,0x34,pSiS->SiS_Pr->Backup_Mode);
                inSISIDXREG(SISPART1,0x14,pSiS->SiS_Pr->Backup_14);
	        inSISIDXREG(SISPART1,0x15,pSiS->SiS_Pr->Backup_15);
	        inSISIDXREG(SISPART1,0x16,pSiS->SiS_Pr->Backup_16);
	        inSISIDXREG(SISPART1,0x17,pSiS->SiS_Pr->Backup_17);
	        inSISIDXREG(SISPART1,0x18,pSiS->SiS_Pr->Backup_18);
	        inSISIDXREG(SISPART1,0x19,pSiS->SiS_Pr->Backup_19);
	        inSISIDXREG(SISPART1,0x1a,pSiS->SiS_Pr->Backup_1a);
	        inSISIDXREG(SISPART1,0x1b,pSiS->SiS_Pr->Backup_1b);
	        inSISIDXREG(SISPART1,0x1c,pSiS->SiS_Pr->Backup_1c);
	        inSISIDXREG(SISPART1,0x1d,pSiS->SiS_Pr->Backup_1d);
	     }
	  }
       }
    }
}