![Antonino A. Daplas](/assets/img/avatar_default.png)
Add memory operand constraint and write-only modifier to the inline assembly to effect the writing of the EDID block to boot_params.edid_info. Without this, gcc would think the EDID query was dead code and would eliminate it. Signed-off-by: Antonino Daplas <adaplas@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
285 lines
6.7 KiB
C
285 lines
6.7 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright 2007 rPath, Inc. - All Rights Reserved
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*
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* This file is part of the Linux kernel, and is made available under
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* the terms of the GNU General Public License version 2.
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*
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* ----------------------------------------------------------------------- */
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/*
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* arch/i386/boot/video-vesa.c
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*
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* VESA text modes
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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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/* VESA information */
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static struct vesa_general_info vginfo;
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static struct vesa_mode_info vminfo;
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__videocard video_vesa;
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static void vesa_store_mode_params_graphics(void);
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static int vesa_probe(void)
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{
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#if defined(CONFIG_VIDEO_VESA) || defined(CONFIG_FIRMWARE_EDID)
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u16 ax;
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u16 mode;
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addr_t mode_ptr;
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struct mode_info *mi;
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int nmodes = 0;
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video_vesa.modes = GET_HEAP(struct mode_info, 0);
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vginfo.signature = VBE2_MAGIC;
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/* Optimistically assume a VESA BIOS is register-clean... */
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ax = 0x4f00;
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asm("int $0x10" : "+a" (ax), "=m" (vginfo) : "D" (&vginfo));
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if (ax != 0x004f ||
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vginfo.signature != VESA_MAGIC ||
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vginfo.version < 0x0102)
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return 0; /* Not present */
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#endif /* CONFIG_VIDEO_VESA || CONFIG_FIRMWARE_EDID */
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#ifdef CONFIG_VIDEO_VESA
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set_fs(vginfo.video_mode_ptr.seg);
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mode_ptr = vginfo.video_mode_ptr.off;
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while ((mode = rdfs16(mode_ptr)) != 0xffff) {
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mode_ptr += 2;
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if (heap_free() < sizeof(struct mode_info))
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break; /* Heap full, can't save mode info */
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if (mode & ~0x1ff)
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continue;
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memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
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ax = 0x4f01;
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asm("int $0x10"
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: "+a" (ax), "=m" (vminfo)
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: "c" (mode), "D" (&vminfo));
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if (ax != 0x004f)
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continue;
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if ((vminfo.mode_attr & 0x15) == 0x05) {
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/* Text Mode, TTY BIOS supported,
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supported by hardware */
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mi = GET_HEAP(struct mode_info, 1);
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mi->mode = mode + VIDEO_FIRST_VESA;
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mi->x = vminfo.h_res;
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mi->y = vminfo.v_res;
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nmodes++;
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} else if ((vminfo.mode_attr & 0x99) == 0x99) {
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#ifdef CONFIG_FB
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/* Graphics mode, color, linear frame buffer
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supported -- register the mode but hide from
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the menu. Only do this if framebuffer is
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configured, however, otherwise the user will
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be left without a screen. */
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mi = GET_HEAP(struct mode_info, 1);
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mi->mode = mode + VIDEO_FIRST_VESA;
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mi->x = mi->y = 0;
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nmodes++;
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#endif
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}
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}
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return nmodes;
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#else
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return 0;
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#endif /* CONFIG_VIDEO_VESA */
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}
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static int vesa_set_mode(struct mode_info *mode)
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{
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u16 ax;
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int is_graphic;
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u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;
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memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
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ax = 0x4f01;
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asm("int $0x10"
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: "+a" (ax), "=m" (vminfo)
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: "c" (vesa_mode), "D" (&vminfo));
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if (ax != 0x004f)
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return -1;
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if ((vminfo.mode_attr & 0x15) == 0x05) {
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/* It's a supported text mode */
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is_graphic = 0;
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} else if ((vminfo.mode_attr & 0x99) == 0x99) {
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/* It's a graphics mode with linear frame buffer */
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is_graphic = 1;
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vesa_mode |= 0x4000; /* Request linear frame buffer */
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} else {
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return -1; /* Invalid mode */
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}
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ax = 0x4f02;
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asm volatile("int $0x10"
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: "+a" (ax)
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: "b" (vesa_mode), "D" (0));
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if (ax != 0x004f)
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return -1;
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graphic_mode = is_graphic;
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if (!is_graphic) {
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/* Text mode */
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force_x = mode->x;
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force_y = mode->y;
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do_restore = 1;
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} else {
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/* Graphics mode */
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vesa_store_mode_params_graphics();
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}
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return 0;
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}
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/* Switch DAC to 8-bit mode */
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static void vesa_dac_set_8bits(void)
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{
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u8 dac_size = 6;
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/* If possible, switch the DAC to 8-bit mode */
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if (vginfo.capabilities & 1) {
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u16 ax, bx;
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ax = 0x4f08;
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bx = 0x0800;
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asm volatile(INT10
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: "+a" (ax), "+b" (bx)
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: : "ecx", "edx", "esi", "edi");
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if (ax == 0x004f)
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dac_size = bx >> 8;
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}
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/* Set the color sizes to the DAC size, and offsets to 0 */
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boot_params.screen_info.red_size = dac_size;
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boot_params.screen_info.green_size = dac_size;
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boot_params.screen_info.blue_size = dac_size;
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boot_params.screen_info.rsvd_size = dac_size;
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boot_params.screen_info.red_pos = 0;
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boot_params.screen_info.green_pos = 0;
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boot_params.screen_info.blue_pos = 0;
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boot_params.screen_info.rsvd_pos = 0;
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}
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/* Save the VESA protected mode info */
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static void vesa_store_pm_info(void)
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{
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u16 ax, bx, di, es;
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ax = 0x4f0a;
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bx = di = 0;
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asm("pushw %%es; "INT10"; movw %%es,%0; popw %%es"
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: "=d" (es), "+a" (ax), "+b" (bx), "+D" (di)
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: : "ecx", "esi");
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if (ax != 0x004f)
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return;
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boot_params.screen_info.vesapm_seg = es;
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boot_params.screen_info.vesapm_off = di;
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}
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/*
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* Save video mode parameters for graphics mode
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*/
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static void vesa_store_mode_params_graphics(void)
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{
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/* Tell the kernel we're in VESA graphics mode */
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boot_params.screen_info.orig_video_isVGA = 0x23;
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/* Mode parameters */
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boot_params.screen_info.vesa_attributes = vminfo.mode_attr;
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boot_params.screen_info.lfb_linelength = vminfo.logical_scan;
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boot_params.screen_info.lfb_width = vminfo.h_res;
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boot_params.screen_info.lfb_height = vminfo.v_res;
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boot_params.screen_info.lfb_depth = vminfo.bpp;
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boot_params.screen_info.pages = vminfo.image_planes;
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boot_params.screen_info.lfb_base = vminfo.lfb_ptr;
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memcpy(&boot_params.screen_info.red_size,
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&vminfo.rmask, 8);
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/* General parameters */
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boot_params.screen_info.lfb_size = vginfo.total_memory;
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if (vminfo.bpp <= 8)
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vesa_dac_set_8bits();
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vesa_store_pm_info();
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}
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/*
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* Save EDID information for the kernel; this is invoked, separately,
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* after mode-setting.
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*/
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void vesa_store_edid(void)
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{
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#ifdef CONFIG_FIRMWARE_EDID
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u16 ax, bx, cx, dx, di;
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/* Apparently used as a nonsense token... */
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memset(&boot_params.edid_info, 0x13, sizeof boot_params.edid_info);
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if (vginfo.version < 0x0200)
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return; /* EDID requires VBE 2.0+ */
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ax = 0x4f15; /* VBE DDC */
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bx = 0x0000; /* Report DDC capabilities */
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cx = 0; /* Controller 0 */
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di = 0; /* ES:DI must be 0 by spec */
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/* Note: The VBE DDC spec is different from the main VESA spec;
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we genuinely have to assume all registers are destroyed here. */
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asm("pushw %%es; movw %2,%%es; "INT10"; popw %%es"
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: "+a" (ax), "+b" (bx)
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: "c" (cx), "D" (di)
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: "esi");
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if (ax != 0x004f)
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return; /* No EDID */
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/* BH = time in seconds to transfer EDD information */
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/* BL = DDC level supported */
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ax = 0x4f15; /* VBE DDC */
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bx = 0x0001; /* Read EDID */
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cx = 0; /* Controller 0 */
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dx = 0; /* EDID block number */
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di =(size_t) &boot_params.edid_info; /* (ES:)Pointer to block */
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asm(INT10
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: "+a" (ax), "+b" (bx), "+d" (dx), "=m" (boot_params.edid_info)
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: "c" (cx), "D" (di)
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: "esi");
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#endif /* CONFIG_FIRMWARE_EDID */
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}
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__videocard video_vesa =
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{
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.card_name = "VESA",
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.probe = vesa_probe,
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.set_mode = vesa_set_mode,
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.xmode_first = VIDEO_FIRST_VESA,
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.xmode_n = 0x200,
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};
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