| /* -*- linux-c -*- ------------------------------------------------------- * |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright 2007 rPath, Inc. - All Rights Reserved |
| * |
| * This file is part of the Linux kernel, and is made available under |
| * the terms of the GNU General Public License version 2. |
| * |
| * ----------------------------------------------------------------------- */ |
| |
| /* |
| * arch/i386/boot/video-bios.c |
| * |
| * Standard video BIOS modes |
| * |
| * We have two options for this; silent and scanned. |
| */ |
| |
| #include "boot.h" |
| #include "video.h" |
| |
| __videocard video_bios; |
| |
| /* Set a conventional BIOS mode */ |
| static int set_bios_mode(u8 mode); |
| |
| static int bios_set_mode(struct mode_info *mi) |
| { |
| return set_bios_mode(mi->mode - VIDEO_FIRST_BIOS); |
| } |
| |
| static int set_bios_mode(u8 mode) |
| { |
| u16 ax; |
| u8 new_mode; |
| |
| ax = mode; /* AH=0x00 Set Video Mode */ |
| asm volatile(INT10 |
| : "+a" (ax) |
| : : "ebx", "ecx", "edx", "esi", "edi"); |
| |
| ax = 0x0f00; /* Get Current Video Mode */ |
| asm volatile(INT10 |
| : "+a" (ax) |
| : : "ebx", "ecx", "edx", "esi", "edi"); |
| |
| do_restore = 1; /* Assume video contents were lost */ |
| new_mode = ax & 0x7f; /* Not all BIOSes are clean with the top bit */ |
| |
| if (new_mode == mode) |
| return 0; /* Mode change OK */ |
| |
| #ifndef _WAKEUP |
| if (new_mode != boot_params.screen_info.orig_video_mode) { |
| /* Mode setting failed, but we didn't end up where we |
| started. That's bad. Try to revert to the original |
| video mode. */ |
| ax = boot_params.screen_info.orig_video_mode; |
| asm volatile(INT10 |
| : "+a" (ax) |
| : : "ebx", "ecx", "edx", "esi", "edi"); |
| } |
| #endif |
| return -1; |
| } |
| |
| static int bios_probe(void) |
| { |
| u8 mode; |
| #ifdef _WAKEUP |
| u8 saved_mode = 0x03; |
| #else |
| u8 saved_mode = boot_params.screen_info.orig_video_mode; |
| #endif |
| u16 crtc; |
| struct mode_info *mi; |
| int nmodes = 0; |
| |
| if (adapter != ADAPTER_EGA && adapter != ADAPTER_VGA) |
| return 0; |
| |
| set_fs(0); |
| crtc = vga_crtc(); |
| |
| video_bios.modes = GET_HEAP(struct mode_info, 0); |
| |
| for (mode = 0x14; mode <= 0x7f; mode++) { |
| if (!heap_free(sizeof(struct mode_info))) |
| break; |
| |
| if (mode_defined(VIDEO_FIRST_BIOS+mode)) |
| continue; |
| |
| if (set_bios_mode(mode)) |
| continue; |
| |
| /* Try to verify that it's a text mode. */ |
| |
| /* Attribute Controller: make graphics controller disabled */ |
| if (in_idx(0x3c0, 0x10) & 0x01) |
| continue; |
| |
| /* Graphics Controller: verify Alpha addressing enabled */ |
| if (in_idx(0x3ce, 0x06) & 0x01) |
| continue; |
| |
| /* CRTC cursor location low should be zero(?) */ |
| if (in_idx(crtc, 0x0f)) |
| continue; |
| |
| mi = GET_HEAP(struct mode_info, 1); |
| mi->mode = VIDEO_FIRST_BIOS+mode; |
| mi->depth = 0; /* text */ |
| mi->x = rdfs16(0x44a); |
| mi->y = rdfs8(0x484)+1; |
| nmodes++; |
| } |
| |
| set_bios_mode(saved_mode); |
| |
| return nmodes; |
| } |
| |
| __videocard video_bios = |
| { |
| .card_name = "BIOS", |
| .probe = bios_probe, |
| .set_mode = bios_set_mode, |
| .unsafe = 1, |
| .xmode_first = VIDEO_FIRST_BIOS, |
| .xmode_n = 0x80, |
| }; |