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authorH. Peter Anvin <hpa@zytor.com>2010-02-19 16:21:38 -0500
committerH. Peter Anvin <hpa@zytor.com>2010-02-19 16:21:38 -0500
commit8e92dc767abb58357e696a48fc3d8ce615a9c01a (patch)
tree5e36758eb4f4bdf57be5d63255b1c82bb9a945e6
parenteb572a5c7951288e265b3e8f9a5d37b6abb2e996 (diff)
x86, setup: Don't skip mode setting for the standard VGA modes
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>
-rw-r--r--arch/x86/boot/video-vga.c9
1 files changed, 1 insertions, 8 deletions
diff --git a/arch/x86/boot/video-vga.c b/arch/x86/boot/video-vga.c
index 819caa1f2008..ed7aeff786b2 100644
--- a/arch/x86/boot/video-vga.c
+++ b/arch/x86/boot/video-vga.c
@@ -42,22 +42,15 @@ static u8 vga_set_basic_mode(void)
42{ 42{
43 struct biosregs ireg, oreg; 43 struct biosregs ireg, oreg;
44 u16 ax; 44 u16 ax;
45 u8 rows;
46 u8 mode; 45 u8 mode;
47 46
48 initregs(&ireg); 47 initregs(&ireg);
49 48
49 /* Query current mode */
50 ax = 0x0f00; 50 ax = 0x0f00;
51 intcall(0x10, &ireg, &oreg); 51 intcall(0x10, &ireg, &oreg);
52 mode = oreg.al; 52 mode = oreg.al;
53 53
54 set_fs(0);
55 rows = rdfs8(0x484); /* rows minus one */
56
57 if ((oreg.ax == 0x5003 || oreg.ax == 0x5007) &&
58 (rows == 0 || rows == 24))
59 return mode;
60
61 if (mode != 3 && mode != 7) 54 if (mode != 3 && mode != 7)
62 mode = 3; 55 mode = 3;
63 56