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x86, setup: un-resequence mode setting for VGA 80x34 and 80x60 modes 

Impact: Fixes these modes on at least one system

The rewrite of the setup code into C resequenced the font setting and
register reprogramming phases of configuring nonstandard VGA modes
which use 480 scan lines in text mode.  However, there exists at least
one board (Micro-Star MS-7383 version 2.0) on which this resequencing
causes an unusable display.

Revert to the original sequencing: set up 480-line mode, install the
font, and then adjust the vertical end register appropriately.

This failure was masked by the fact that the 480-line setup was broken
until checkin 5f64135612 (therefore this
is not a -stable candidate bug fix.)

Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
H. Peter Anvin 2009-04-07 10:59:25 -07:00
parent f7d7f866ba
commit 1e274a5827
1 changed files with 23 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
arch/x86/boot/video-vga.c
View File

@ -129,22 +129,18 @@ u16 vga_crtc(void)
return (inb(0x3cc) & 1) ? 0x3d4 : 0x3b4;
}
static void vga_set_480_scanlines(int lines)
static void vga_set_480_scanlines(void)
{
u16 crtc; /* CRTC base address */
u8 csel; /* CRTC miscellaneous output register */
u8 ovfw; /* CRTC overflow register */
int end = lines-1;
crtc = vga_crtc();
ovfw = 0x3c | ((end >> (8-1)) & 0x02) | ((end >> (9-6)) & 0x40);
out_idx(0x0c, crtc, 0x11); /* Vertical sync end, unlock CR0-7 */
out_idx(0x0b, crtc, 0x06); /* Vertical total */
out_idx(ovfw, crtc, 0x07); /* Vertical overflow */
out_idx(0x3e, crtc, 0x07); /* Vertical overflow */
out_idx(0xea, crtc, 0x10); /* Vertical sync start */
out_idx(end, crtc, 0x12); /* Vertical display end */
out_idx(0xdf, crtc, 0x12); /* Vertical display end */
out_idx(0xe7, crtc, 0x15); /* Vertical blank start */
out_idx(0x04, crtc, 0x16); /* Vertical blank end */
csel = inb(0x3cc);
@ -153,21 +149,38 @@ static void vga_set_480_scanlines(int lines)
outb(csel, 0x3c2);
}
static void vga_set_vertical_end(int lines)
{
u16 crtc; /* CRTC base address */
u8 ovfw; /* CRTC overflow register */
int end = lines-1;
crtc = vga_crtc();
ovfw = 0x3c | ((end >> (8-1)) & 0x02) | ((end >> (9-6)) & 0x40);
out_idx(ovfw, crtc, 0x07); /* Vertical overflow */
out_idx(end, crtc, 0x12); /* Vertical display end */
}
static void vga_set_80x30(void)
{
vga_set_480_scanlines(30*16);
vga_set_480_scanlines();
vga_set_vertical_end(30*16);
}
static void vga_set_80x34(void)
{
vga_set_480_scanlines();
vga_set_14font();
vga_set_480_scanlines(34*14);
vga_set_vertical_end(34*14);
}
static void vga_set_80x60(void)
{
vga_set_480_scanlines();
vga_set_8font();
vga_set_480_scanlines(60*8);
vga_set_vertical_end(60*8);
}
static int vga_set_mode(struct mode_info *mode)