diff options
Diffstat (limited to 'arch/x86/boot/video-mode.c')
| -rw-r--r-- | arch/x86/boot/video-mode.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/x86/boot/video-mode.c b/arch/x86/boot/video-mode.c new file mode 100644 index 000000000..9ada55dc1 --- /dev/null +++ b/arch/x86/boot/video-mode.c @@ -0,0 +1,171 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007-2008 rPath, Inc. - All Rights Reserved + * + * ----------------------------------------------------------------------- */ + +/* + * arch/i386/boot/video-mode.c + * + * Set the video mode. This is separated out into a different + * file in order to be shared with the ACPI wakeup code. + */ + +#include "boot.h" +#include "video.h" +#include "vesa.h" + +#include <uapi/asm/boot.h> + +/* + * Common variables + */ +int adapter; /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */ +int force_x, force_y; /* Don't query the BIOS for cols/rows */ +int do_restore; /* Screen contents changed during mode flip */ +int graphic_mode; /* Graphic mode with linear frame buffer */ + +/* Probe the video drivers and have them generate their mode lists. */ +void probe_cards(int unsafe) +{ + struct card_info *card; + static u8 probed[2]; + + if (probed[unsafe]) + return; + + probed[unsafe] = 1; + + for (card = video_cards; card < video_cards_end; card++) { + if (card->unsafe == unsafe) { + if (card->probe) + card->nmodes = card->probe(); + else + card->nmodes = 0; + } + } +} + +/* Test if a mode is defined */ +int mode_defined(u16 mode) +{ + struct card_info *card; + struct mode_info *mi; + int i; + + for (card = video_cards; card < video_cards_end; card++) { + mi = card->modes; + for (i = 0; i < card->nmodes; i++, mi++) { + if (mi->mode == mode) + return 1; + } + } + + return 0; +} + +/* Set mode (without recalc) */ +static int raw_set_mode(u16 mode, u16 *real_mode) +{ + int nmode, i; + struct card_info *card; + struct mode_info *mi; + + /* Drop the recalc bit if set */ + mode &= ~VIDEO_RECALC; + + /* Scan for mode based on fixed ID, position, or resolution */ + nmode = 0; + for (card = video_cards; card < video_cards_end; card++) { + mi = card->modes; + for (i = 0; i < card->nmodes; i++, mi++) { + int visible = mi->x || mi->y; + + if ((mode == nmode && visible) || + mode == mi->mode || + mode == (mi->y << 8)+mi->x) { + *real_mode = mi->mode; + return card->set_mode(mi); + } + + if (visible) + nmode++; + } + } + + /* Nothing found? Is it an "exceptional" (unprobed) mode? */ + for (card = video_cards; card < video_cards_end; card++) { + if (mode >= card->xmode_first && + mode < card->xmode_first+card->xmode_n) { + struct mode_info mix; + *real_mode = mix.mode = mode; + mix.x = mix.y = 0; + return card->set_mode(&mix); + } + } + + /* Otherwise, failure... */ + return -1; +} + +/* + * Recalculate the vertical video cutoff (hack!) + */ +static void vga_recalc_vertical(void) +{ + unsigned int font_size, rows; + u16 crtc; + u8 pt, ov; + + set_fs(0); + font_size = rdfs8(0x485); /* BIOS: font size (pixels) */ + rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */ + + rows *= font_size; /* Visible scan lines */ + rows--; /* ... minus one */ + + crtc = vga_crtc(); + + pt = in_idx(crtc, 0x11); + pt &= ~0x80; /* Unlock CR0-7 */ + out_idx(pt, crtc, 0x11); + + out_idx((u8)rows, crtc, 0x12); /* Lower height register */ + + ov = in_idx(crtc, 0x07); /* Overflow register */ + ov &= 0xbd; + ov |= (rows >> (8-1)) & 0x02; + ov |= (rows >> (9-6)) & 0x40; + out_idx(ov, crtc, 0x07); +} + +/* Set mode (with recalc if specified) */ +int set_mode(u16 mode) +{ + int rv; + u16 real_mode; + + /* Very special mode numbers... */ + if (mode == VIDEO_CURRENT_MODE) + return 0; /* Nothing to do... */ + else if (mode == NORMAL_VGA) + mode = VIDEO_80x25; + else if (mode == EXTENDED_VGA) + mode = VIDEO_8POINT; + + rv = raw_set_mode(mode, &real_mode); + if (rv) + return rv; + + if (mode & VIDEO_RECALC) + vga_recalc_vertical(); + + /* Save the canonical mode number for the kernel, not + an alias, size specification or menu position */ +#ifndef _WAKEUP + boot_params.hdr.vid_mode = real_mode; +#endif + return 0; +} |