leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

x86, setup: Don't skip mode setting for the standard VGA modes

Browse Source 
The code for setting standard VGA modes probes for the current mode,
and skips the mode setting if the mode is 3 (color text 80x25) or 7
(mono text 80x25).  Unfortunately, there are BIOSes, including the
VMware BIOS, which report the previous mode if function 0F is queried
while the screen is in a VESA mode, and of course, nothing can help a
mode poked directly into the hardware.

As such, the safe option is to set the mode anyway, and only query to
see if we should be using mode 7 rather than mode 3.  People who don't
want any mode setting at all should probably use vga=0x0f04
(VIDEO_CURRENT_MODE).  It's possible that should be the kernel
default.

Reported-by Rene Arends <R.R.Arends@hro.nl>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <tip-*@git.kernel.org>
This commit is contained in:
H. Peter Anvin 2010-02-19 13:21:38 -08:00
parent eb572a5c79
commit 8e92dc767a
1 changed files with 1 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
arch/x86/boot/video-vga.c
View File

@ -42,22 +42,15 @@ static u8 vga_set_basic_mode(void)
{
struct biosregs ireg, oreg;
u16 ax;
u8 rows;
u8 mode;
initregs(&ireg);
/* Query current mode */
ax = 0x0f00;
intcall(0x10, &ireg, &oreg);
mode = oreg.al;
set_fs(0);
rows = rdfs8(0x484); /* rows minus one */
if ((oreg.ax == 0x5003 || oreg.ax == 0x5007) &&
(rows == 0 || rows == 24))
return mode;
if (mode != 3 && mode != 7)
mode = 3;