172 lines
3.7 KiB
C
172 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright 2007-2008 rPath, Inc. - All Rights Reserved
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*
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* ----------------------------------------------------------------------- */
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/*
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* arch/i386/boot/video-mode.c
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*
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* Set the video mode. This is separated out into a different
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* file in order to be shared with the ACPI wakeup code.
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*/
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#include "boot.h"
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#include "video.h"
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#include "vesa.h"
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#include <uapi/asm/boot.h>
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/*
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* Common variables
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*/
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int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */
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int force_x, force_y; /* Don't query the BIOS for cols/rows */
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int do_restore; /* Screen contents changed during mode flip */
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int graphic_mode; /* Graphic mode with linear frame buffer */
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/* Probe the video drivers and have them generate their mode lists. */
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void probe_cards(int unsafe)
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{
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struct card_info *card;
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static u8 probed[2];
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if (probed[unsafe])
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return;
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probed[unsafe] = 1;
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for (card = video_cards; card < video_cards_end; card++) {
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if (card->unsafe == unsafe) {
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if (card->probe)
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card->nmodes = card->probe();
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else
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card->nmodes = 0;
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}
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}
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}
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/* Test if a mode is defined */
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int mode_defined(u16 mode)
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{
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struct card_info *card;
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struct mode_info *mi;
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int i;
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for (card = video_cards; card < video_cards_end; card++) {
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mi = card->modes;
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for (i = 0; i < card->nmodes; i++, mi++) {
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if (mi->mode == mode)
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return 1;
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}
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}
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return 0;
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}
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/* Set mode (without recalc) */
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static int raw_set_mode(u16 mode, u16 *real_mode)
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{
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int nmode, i;
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struct card_info *card;
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struct mode_info *mi;
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/* Drop the recalc bit if set */
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mode &= ~VIDEO_RECALC;
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/* Scan for mode based on fixed ID, position, or resolution */
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nmode = 0;
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for (card = video_cards; card < video_cards_end; card++) {
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mi = card->modes;
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for (i = 0; i < card->nmodes; i++, mi++) {
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int visible = mi->x || mi->y;
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if ((mode == nmode && visible) ||
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mode == mi->mode ||
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mode == (mi->y << 8)+mi->x) {
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*real_mode = mi->mode;
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return card->set_mode(mi);
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}
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if (visible)
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nmode++;
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}
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}
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/* Nothing found? Is it an "exceptional" (unprobed) mode? */
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for (card = video_cards; card < video_cards_end; card++) {
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if (mode >= card->xmode_first &&
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mode < card->xmode_first+card->xmode_n) {
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struct mode_info mix;
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*real_mode = mix.mode = mode;
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mix.x = mix.y = 0;
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return card->set_mode(&mix);
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}
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}
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/* Otherwise, failure... */
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return -1;
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}
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/*
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* Recalculate the vertical video cutoff (hack!)
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*/
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static void vga_recalc_vertical(void)
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{
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unsigned int font_size, rows;
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u16 crtc;
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u8 pt, ov;
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set_fs(0);
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font_size = rdfs8(0x485); /* BIOS: font size (pixels) */
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rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */
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rows *= font_size; /* Visible scan lines */
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rows--; /* ... minus one */
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crtc = vga_crtc();
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pt = in_idx(crtc, 0x11);
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pt &= ~0x80; /* Unlock CR0-7 */
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out_idx(pt, crtc, 0x11);
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out_idx((u8)rows, crtc, 0x12); /* Lower height register */
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ov = in_idx(crtc, 0x07); /* Overflow register */
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ov &= 0xbd;
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ov |= (rows >> (8-1)) & 0x02;
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ov |= (rows >> (9-6)) & 0x40;
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out_idx(ov, crtc, 0x07);
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}
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/* Set mode (with recalc if specified) */
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int set_mode(u16 mode)
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{
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int rv;
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u16 real_mode;
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/* Very special mode numbers... */
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if (mode == VIDEO_CURRENT_MODE)
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return 0; /* Nothing to do... */
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else if (mode == NORMAL_VGA)
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mode = VIDEO_80x25;
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else if (mode == EXTENDED_VGA)
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mode = VIDEO_8POINT;
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rv = raw_set_mode(mode, &real_mode);
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if (rv)
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return rv;
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if (mode & VIDEO_RECALC)
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vga_recalc_vertical();
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/* Save the canonical mode number for the kernel, not
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an alias, size specification or menu position */
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#ifndef _WAKEUP
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boot_params.hdr.vid_mode = real_mode;
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#endif
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return 0;
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}
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