diff options
| author | H. Peter Anvin <hpa@linux.intel.com> | 2009-04-07 10:59:25 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2009-04-07 10:59:25 -0700 |
| commit | 1e274a582710e95d93b86e8d47e9fcce4ca09d01 (patch) | |
| tree | d91aa694ed60fe170baa613826f8e8d74eddc229 /arch/x86/boot | |
| parent | f7d7f866baacc283967ce82ebdfe5d2801059a11 (diff) | |
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 5f641356127712fbdce0eee120e5ce115860c17f (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>
Diffstat (limited to 'arch/x86/boot')
| -rw-r--r-- | arch/x86/boot/video-vga.c | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/arch/x86/boot/video-vga.c b/arch/x86/boot/video-vga.c index 95d86ce0421..9e0587a3776 100644 --- a/arch/x86/boot/video-vga.c +++ b/arch/x86/boot/video-vga.c @@ -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) |