/* Copyright (c) 2005 Advanced Micro Devices, Inc. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. * * Neither the name of the Advanced Micro Devices, Inc. nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * */ /* * This file contains routines to set modes using the VGA registers. * Since this file is for the first generation graphics unit, it interfaces * to SoftVGA registers. It works for both VSA1 and VSA2. * */ /* SoftVGA Extended CRTC register indices and bit definitions */ #define CRTC_EXTENDED_REGISTER_LOCK 0x30 #define CRTC_MODE_SWITCH_CONTROL 0x3F /* BIT DEFINITIONS */ #define CRTC_BIT_16BPP 0x01 #define CRTC_BIT_555 0x02 /* LOCAL ROUTINE DEFINITIONS */ int gu1_detect_vsa2(void); /*---------------------------------*/ /* MODE TABLES FOR VGA REGISTERS */ /*---------------------------------*/ /* FOR SoftVGA, the CRTC_EXTENDED_ADDRESS_CONTROL (0x43) is always equal to * 0x03 for a packed linear frame buffer organization. The * CRTC_EXTENDED_DAC_CONTROL (0x4B) is always equal to 0x03 to work with * older versions of VSA1 (that needed to specify 8 or 16 bit bus to an * external RAMDAC. This is not used in VSA2. The clock frequency is * specified in register 0x4D if clock control (0x4C) is set to 0x80. * Higher resolutions (1280x1024) use the CRTC_EXTENDED_VERTICAL_TIMING * register (index 0x41). */ gfx_vga_struct gfx_vga_modes[] = { /*--------------------------------------------------------------------------*/ { 640, 480, 60, /* 640x480 */ 25, /* 25 MHz clock = 60 Hz refresh rate */ 0xE3, /* miscOutput register */ { 0x5F, 0x4F, 0x50, 0x82, 0x54, 0x80, 0x0B, 0x3E, /* standard CRTC */ 0x80, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xEA, 0x0C, 0xDF, 0x50, 0x00, 0xE7, 0x04, 0xE3, 0xFF}, { 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00} }, /*--------------------------------------------------------------------------*/ { 640, 480, 72, /* 640x480 */ 29, /* 29 MHz clock = 72 Hz refresh rate */ 0xE3, /* miscOutput register */ { 0x63, 0x4f, 0x50, 0x86, 0x55, 0x99, 0x06, 0x3e, /* standard CRTC */ 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe9, 0x0c, 0xdf, 0x00, 0x00, 0xe7, 0x00, 0xe3, 0xff}, { 0x6D, 0x00, 0x00, 0x03, 0x00, 0x01, 0x01, 0x00, /* extended CRTC */ 0x00, 0x00, 0x01, 0x08, 0x80, 0x1F, 0x00, 0x4B} }, /*--------------------------------------------------------------------------*/ { 640, 480, 75, /* 640x480 */ 31, /* 31.5 MHz clock = 75 Hz refresh rate */ 0xE3, /* miscOutput register */ { 0x64, 0x4F, 0x4F, 0x88, 0x54, 0x9B, 0xF2, 0x1F, /* standard CRTC */ 0x80, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE1, 0x04, 0xDF, 0x50, 0x00, 0xDF, 0xF3, 0xE3, 0xFF}, { 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x00, 0x03, 0x80, 0x1F, 0x00, 0x00} }, /*--------------------------------------------------------------------------*/ { 800, 600, 60, /* 800x600 */ 40, /* 40 MHz clock = 60 Hz refresh rate */ 0x23, /* miscOutput register */ { 0x7F, 0x63, 0x64, 0x82, 0x6B, 0x1B, 0x72, 0xF0, /* standard CRTC */ 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x59, 0x0D, 0x57, 0x64, 0x00, 0x57, 0x73, 0xE3, 0xFF}, { 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x00, 0x03, 0x80, 0x28, 0x00, 0x00} }, /*--------------------------------------------------------------------------*/ { 800, 600, 72, /* 800x600 */ 47, /* 47 MHz clock = 72 Hz refresh rate */ 0x2B, /* miscOutput register */ { 0x7D, 0x63, 0x63, 0x81, 0x6D, 0x1B, 0x98, 0xF0, /* standard CRTC */ 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x7D, 0x03, 0x57, 0x00, 0x00, 0x57, 0x9A, 0xE3, 0xFF}, { 0x6F, 0x00, 0x00, 0x03, 0x00, 0x01, 0x01, 0x00, /* extended CRTC */ 0x00, 0x00, 0x01, 0x08, 0x80, 0x32, 0x00, 0x4B} }, /*--------------------------------------------------------------------------*/ { 800, 600, 75, /* 800x600 */ 49, /* 49.5 MHz clock = 75 Hz refresh rate */ 0x23, /* miscOutput register */ { 0x7F, 0x63, 0x63, 0x83, 0x68, 0x11, 0x6F, 0xF0, /* standard CRTC */ 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x59, 0x1C, 0x57, 0x64, 0x00, 0x57, 0x70, 0xE3, 0xFF}, { 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x00, 0x03, 0x80, 0x31, 0x00, 0x00} }, /*--------------------------------------------------------------------------*/ { 1024, 768, 60, /* 1024x768 */ 65, /* 65 MHz clock = 60 Hz refresh rate */ 0xE3, /* miscOutput register */ { 0xA3, 0x7F, 0x80, 0x86, 0x85, 0x96, 0x24, 0xF5, /* standard CRTC */ 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x0A, 0xFF, 0x80, 0x00, 0xFF, 0x25, 0xE3, 0xFF}, { 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x00, 0x03, 0x80, 0x41, 0x00, 0x00} }, /*--------------------------------------------------------------------------*/ { 1024, 768, 70, /* 1024x768 */ 76, /* 76 MHz clock = 70 Hz refresh rate */ 0x2B, /* miscOutput register */ { 0xA1, 0x7F, 0x7F, 0x85, 0x85, 0x95, 0x24, 0xF5, /* standard CRTC */ 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x09, 0xFF, 0x00, 0x00, 0xFF, 0x26, 0xE3, 0xFF}, { 0x62, 0x00, 0x00, 0x03, 0x00, 0x01, 0x01, 0x00, /* extended CRTC */ 0x00, 0x00, 0x01, 0x02, 0x80, 0x4B, 0x00, 0x4B} }, /*--------------------------------------------------------------------------*/ { 1024, 768, 75, /* 1024x768 */ 79, /* 79 MHz clock = 75 Hz refresh rate */ 0xE3, /* miscOutput register */ { 0x9F, 0x7F, 0x7F, 0x83, 0x84, 0x8F, 0x1E, 0xF5, /* standard CRTC */ 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x04, 0xFF, 0x80, 0x00, 0xFF, 0x1F, 0xE3, 0xFF}, { 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x00, 0x03, 0x80, 0x4F, 0x00, 0x00} }, /*--------------------------------------------------------------------------*/ { 1280, 1024, 60, /* 1280x1024 */ 108, /* 108 MHz clock = 60 Hz refresh rate */ 0x23, /* miscOutput register */ { 0xCF, 0x9F, 0xA0, 0x92, 0xAA, 0x19, 0x28, 0x52, /* standard CRTC */ 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x04, 0xFF, 0xA0, 0x00, 0x00, 0x29, 0xE3, 0xFF}, { 0x00, 0x51, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x00, 0x03, 0x80, 0x6C, 0x00, 0x00} }, /*--------------------------------------------------------------------------*/ { 1280, 1024, 75, /* 1280x1024 */ 135, /* 135 MHz clock = 75 Hz refresh rate */ 0x23, /* miscOutput register */ { 0xCE, 0x9F, 0x9F, 0x92, 0xA4, 0x15, 0x28, 0x52, /* standard CRTC */ 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x04, 0xFF, 0xA0, 0x00, 0x00, 0x29, 0xE3, 0xFF}, { 0x00, 0x51, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x00, 0x03, 0x80, 0x87, 0x00, 0x00} }, /*--------------------------------------------------------------------------*/ { 1280, 1024, 85, /* 1280x1024 */ 159, /* 159 MHz clock = 85 Hz refresh rate */ 0x2B, /* miscOutput register */ { 0xD3, 0x9F, 0xA0, 0x98, 0xA8, 0x9C, 0x2E, 0x5A, /* standard CRTC */ 0x00, 0x60, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x04, 0xFF, 0x00, 0x00, 0xFF, 0x30, 0xE3, 0xFF}, { 0x6B, 0x41, 0x00, 0x03, 0x00, 0x01, 0x00, 0x00, /* extended CRTC */ 0x00, 0x00, 0x01, 0x00, 0x80, 0x9D, 0x00, 0x4B} }, /*--------------------------------------------------------------------------*/ }; #define GFX_VGA_MODES sizeof(gfx_vga_modes)/sizeof(gfx_vga_struct) /*---------------------------------------------------------------------------- * gfx_get_softvga_active * * This returns the active status of SoftVGA *---------------------------------------------------------------------------- */ int gfx_get_softvga_active(void) { unsigned short crtcindex, crtcdata; if (gu1_detect_vsa2()) return (gfx_get_vsa2_softvga_enable()); crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4; crtcdata = crtcindex + 1; OUTB(crtcindex, CRTC_MODE_SWITCH_CONTROL); return (INB(crtcdata) & 0x1); } /*---------------------------------------------------------------------------- * gfx_vga_test_pci * * This routine looks for the VGA PCI header. It checks to see that bit 1 * of the command register is writable to know that SoftVGA is trapping * the PCI config cuscles. If SoftVGA is not emulating the header, the * hardware will still respond with the proper device ID, etc. * * We need to know that SoftVGA is really there so that we can set the * command register and have the proper effect (enable trapping of VGA). * Otherwise, if we enable VGA via the PCI header, trapping really won't be * enabled and the VGA register writes will go out to the external card. *---------------------------------------------------------------------------- */ int gfx_vga_test_pci(void) { int softvga = 1; unsigned long value; value = gfx_pci_config_read(0x80009400); if ((value & 0x0000FFFF) != 0x1078) softvga = 0; else { value = gfx_pci_config_read(0x80009404); gfx_pci_config_write(0x80009404, value | 0x02); if (!(gfx_pci_config_read(0x80009404) & 0x02)) softvga = 0; gfx_pci_config_write(0x80009404, value); } return (softvga); } /*---------------------------------------------------------------------------- * gfx_vga_get_pci_command * * This routine returns the value of the PCI command register. *---------------------------------------------------------------------------- */ unsigned char gfx_vga_get_pci_command(void) { unsigned long value; value = gfx_pci_config_read(0x80009404); return ((unsigned char)value); } /*---------------------------------------------------------------------------- * gfx_vga_set_pci_command * * This routine writes the value of the PCI command register. It is used * to enable or disable SoftVGA. * * Bit 0: Enable VGA IO * Bit 1: Enable VGA memory *---------------------------------------------------------------------------- */ int gfx_vga_set_pci_command(unsigned char command) { unsigned long value; value = gfx_pci_config_read(0x80009404) & 0xFFFFFF00; value |= (unsigned long)command; gfx_pci_config_write(0x80009404, value); return (GFX_STATUS_OK); } /*---------------------------------------------------------------------------- * gfx_vga_seq_reset * * This routine enables or disables SoftVGA. It is used to make SoftVGA * "be quiet" and not interfere with any of the direct hardware access from * Durango. For VSA1, the sequencer is reset to stop text redraws. VSA2 may * provide a better way to have SoftVGA sit in the background. *---------------------------------------------------------------------------- */ int gfx_vga_seq_reset(int reset) { OUTB(0x3C4, 0); OUTB(0x3C5, (unsigned char)(reset ? 0x00 : 0x03)); return (GFX_STATUS_OK); } /*---------------------------------------------------------------------------- * gfx_vga_set_graphics_bits * * This routine sets the standard VGA sequencer, graphics controller, and * attribute registers to appropriate values for a graphics mode (packed, * 8 BPP or greater). This is also known as "VESA" modes. The timings for * a particular mode are handled by the CRTC registers, which are set by * the "gfx_vga_restore" routine. Most OSs that use VGA to set modes save * and restore the standard VGA registers themselves, which is why these * registers are not part of the save/restore paradigm. *---------------------------------------------------------------------------- */ int gfx_vga_set_graphics_bits(void) { /* SET GRAPHICS BIT IN GRAPHICS CONTROLLER REG 0x06 */ OUTB(0x3CE, 0x06); OUTB(0x3CF, 0x01); /* SET GRAPHICS BIT IN ATTRIBUTE CONTROLLER REG 0x10 */ INB(0x3BA); /* Reset flip-flop */ INB(0x3DA); OUTB(0x3C0, 0x10); OUTB(0x3C0, 0x01); return (GFX_STATUS_OK); } /*---------------------------------------------------------------------------- * gfx_vga_mode * * This routine searches the VGA mode table for a match of the specified * mode and then fills in the VGA structure with the associated VGA register * values. The "gfx_vga_restore" routine can then be called to actually * set the mode. *---------------------------------------------------------------------------- */ int gfx_vga_mode(gfx_vga_struct * vga, int xres, int yres, int bpp, int hz) { unsigned int i; unsigned short pitch; for (i = 0; i < GFX_VGA_MODES; i++) { if ((gfx_vga_modes[i].xsize == xres) && (gfx_vga_modes[i].ysize == yres) && (gfx_vga_modes[i].hz == hz)) { /* COPY ENTIRE STRUCTURE FROM THE TABLE */ *vga = gfx_vga_modes[i]; /* SET PITCH TO 1K OR 2K */ /* CRTC_EXTENDED_OFFSET index is 0x45, so offset = 0x05 */ pitch = (unsigned short)xres; if (bpp > 8) pitch <<= 1; if (pitch <= 1024) pitch = 1024 >> 3; else pitch = 2048 >> 3; vga->stdCRTCregs[0x13] = (unsigned char)pitch; vga->extCRTCregs[0x05] = (unsigned char)((pitch >> 8) & 0x03); /* SET PROPER COLOR DEPTH VALUE */ /* CRTC_EXTENDED_COLOR_CONTROL index is 0x46, so offset = 0x06 */ switch (bpp) { case 15: vga->extCRTCregs[0x06] = CRTC_BIT_16BPP | CRTC_BIT_555; break; case 16: vga->extCRTCregs[0x06] = CRTC_BIT_16BPP; break; default: vga->extCRTCregs[0x06] = 0; break; } return (GFX_STATUS_OK); } } return (GFX_STATUS_UNSUPPORTED); } /*---------------------------------------------------------------------------- * gfx_vga_pitch * * This routine updates the VGA regisers in the specified VGA structure for * the specified pitch. It does not program the hardware. *---------------------------------------------------------------------------- */ int gfx_vga_pitch(gfx_vga_struct * vga, unsigned short pitch) { pitch >>= 3; vga->stdCRTCregs[0x13] = (unsigned char)pitch; vga->extCRTCregs[0x05] = (unsigned char)((pitch >> 8) & 0x03); return (0); } /*---------------------------------------------------------------------------- * gfx_vga_save * * This routine saves the state of the VGA registers into the specified * structure. Flags indicate what portions of the register state need to * be saved. *---------------------------------------------------------------------------- */ int gfx_vga_save(gfx_vga_struct * vga, int flags) { int i; unsigned short crtcindex, crtcdata; crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4; crtcdata = crtcindex + 1; /* CHECK MISCELLANEOUS OUTPUT FLAG */ if (flags & GFX_VGA_FLAG_MISC_OUTPUT) { /* SAVE MISCCELLANEOUS OUTPUT REGISTER */ vga->miscOutput = INB(0x3CC); } /* CHECK STANDARD CRTC FLAG */ if (flags & GFX_VGA_FLAG_STD_CRTC) { /* SAVE STANDARD CRTC REGISTERS */ for (i = 0; i < GFX_STD_CRTC_REGS; i++) { OUTB(crtcindex, (unsigned char)i); vga->stdCRTCregs[i] = INB(crtcdata); } } /* CHECK EXTENDED CRTC FLAG */ if (flags & GFX_VGA_FLAG_EXT_CRTC) { /* SAVE EXTENDED CRTC REGISTERS */ for (i = 0; i < GFX_EXT_CRTC_REGS; i++) { OUTB(crtcindex, (unsigned char)(0x40 + i)); vga->extCRTCregs[i] = INB(crtcdata); } } return (0); } /*---------------------------------------------------------------------------- * gfx_vga_clear_extended * * This routine clears the extended SoftVGA register values to have SoftVGA * behave like standard VGA. *---------------------------------------------------------------------------- */ void gfx_vga_clear_extended(void) { int i; unsigned short crtcindex, crtcdata; crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4; crtcdata = crtcindex + 1; OUTB(crtcindex, 0x30); OUTB(crtcdata, 0x57); OUTB(crtcdata, 0x4C); for (i = 0x40; i <= 0x4F; i++) { OUTB(crtcindex, (unsigned char)i); OUTB(crtcdata, 0); } OUTB(crtcindex, 0x30); OUTB(crtcdata, 0x00); } /*---------------------------------------------------------------------------- * gfx_vga_restore * * This routine restores the state of the VGA registers from the specified * structure. Flags indicate what portions of the register state need to * be saved. *---------------------------------------------------------------------------- */ int gfx_vga_restore(gfx_vga_struct * vga, int flags) { int i; unsigned short crtcindex, crtcdata; crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4; crtcdata = crtcindex + 1; /* CHECK MISCELLANEOUS OUTPUT FLAG */ if (flags & GFX_VGA_FLAG_MISC_OUTPUT) { /* RESTORE MISCELLANEOUS OUTPUT REGISTER VALUE */ OUTB(0x3C2, vga->miscOutput); } /* CHECK STANDARD CRTC FLAG */ if (flags & GFX_VGA_FLAG_STD_CRTC) { /* UNLOCK STANDARD CRTC REGISTERS */ OUTB(crtcindex, 0x11); OUTB(crtcdata, 0); /* RESTORE STANDARD CRTC REGISTERS */ for (i = 0; i < GFX_STD_CRTC_REGS; i++) { OUTB(crtcindex, (unsigned char)i); OUTB(crtcdata, vga->stdCRTCregs[i]); } } /* CHECK EXTENDED CRTC FLAG */ if (flags & GFX_VGA_FLAG_EXT_CRTC) { /* UNLOCK EXTENDED CRTC REGISTERS */ OUTB(crtcindex, 0x30); OUTB(crtcdata, 0x57); OUTB(crtcdata, 0x4C); /* RESTORE EXTENDED CRTC REGISTERS */ for (i = 0; i < GFX_EXT_CRTC_REGS; i++) { OUTB(crtcindex, (unsigned char)(0x40 + i)); OUTB(crtcdata, vga->extCRTCregs[i]); } /* LOCK EXTENDED CRTC REGISTERS */ OUTB(crtcindex, 0x30); OUTB(crtcdata, 0x00); /* CHECK IF DIRECT FRAME BUFFER MODE (VESA MODE) */ if (vga->extCRTCregs[0x03] & 1) { /* SET BORDER COLOR TO BLACK */ /* This really should be another thing saved/restored, but */ /* Durango currently doesn't do the attr controller registers. */ INB(0x3BA); /* Reset flip-flop */ INB(0x3DA); OUTB(0x3C0, 0x11); OUTB(0x3C0, 0x00); } } return (0); } /*---------------------------------------------------------------------------- * gfx_vga_mode_switch * * This routine programs the SoftVGA register to indicate that a mode switch * is in progress. This results in a cleaner mode switch since SoftVGA will * not validate the hardware with intermediate values. *---------------------------------------------------------------------------- */ int gfx_vga_mode_switch(int active) { unsigned short crtcindex, crtcdata; crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4; crtcdata = crtcindex + 1; /* UNLOCK EXTENDED CRTC REGISTERS */ OUTB(crtcindex, CRTC_EXTENDED_REGISTER_LOCK); OUTB(crtcdata, 0x57); OUTB(crtcdata, 0x4C); /* SIGNAL THE BEGINNING OR END OF THE MODE SWITCH */ /* SoftVGA will hold off validating the back end hardware. */ OUTB(crtcindex, CRTC_MODE_SWITCH_CONTROL); active = active ? 1 : 0; OUTB(crtcdata, (unsigned char)active); /* WAIT UNTIL SOFTVGA HAS VALIDATED MODE IF ENDING MODE SWITCH */ /* This is for VSA1 only, where SoftVGA waits until the next */ /* vertical blank to validate the hardware state. */ if ((!active) && (!(gu1_detect_vsa2()))) { OUTB(crtcindex, 0x33); while (INB(crtcdata) & 0x80) ; } /* LOCK EXTENDED CRTC REGISTERS */ OUTB(crtcindex, CRTC_EXTENDED_REGISTER_LOCK); OUTB(crtcdata, 0x00); return (0); } /*---------------------------------------------------------------------------- * gu1_detect_vsa2 * * This routine detects if VSA2 is present. The interface to SoftVGA * changed slightly. *---------------------------------------------------------------------------- */ int gu1_detect_vsa2(void) { unsigned short crtcindex, crtcdata; crtcindex = (INB(0x3CC) & 0x01) ? 0x3D4 : 0x3B4; crtcdata = crtcindex + 1; OUTB(crtcindex, 0x35); if (INB(crtcdata) != 'C') return (0); OUTB(crtcindex, 0x36); if (INB(crtcdata) != 'X') return (0); return (1); } /* END OF FILE */