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Diffstat (limited to 'arch/x86/boot/video-vga.c')
-rw-r--r--arch/x86/boot/video-vga.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/arch/x86/boot/video-vga.c b/arch/x86/boot/video-vga.c
index 5d4742ed4aa..95d86ce0421 100644
--- a/arch/x86/boot/video-vga.c
+++ b/arch/x86/boot/video-vga.c
@@ -129,41 +129,45 @@ u16 vga_crtc(void)
return (inb(0x3cc) & 1) ? 0x3d4 : 0x3b4;
}
-static void vga_set_480_scanlines(int end)
+static void vga_set_480_scanlines(int lines)
{
- u16 crtc;
- u8 csel;
+ 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(0x3e, crtc, 0x07); /* Vertical overflow */
+ out_idx(ovfw, crtc, 0x07); /* Vertical overflow */
out_idx(0xea, crtc, 0x10); /* Vertical sync start */
- out_idx(end, crtc, 0x12); /* Vertical display end */
+ out_idx(end, crtc, 0x12); /* Vertical display end */
out_idx(0xe7, crtc, 0x15); /* Vertical blank start */
out_idx(0x04, crtc, 0x16); /* Vertical blank end */
csel = inb(0x3cc);
csel &= 0x0d;
csel |= 0xe2;
- outb(csel, 0x3cc);
+ outb(csel, 0x3c2);
}
static void vga_set_80x30(void)
{
- vga_set_480_scanlines(0xdf);
+ vga_set_480_scanlines(30*16);
}
static void vga_set_80x34(void)
{
vga_set_14font();
- vga_set_480_scanlines(0xdb);
+ vga_set_480_scanlines(34*14);
}
static void vga_set_80x60(void)
{
vga_set_8font();
- vga_set_480_scanlines(0xdf);
+ vga_set_480_scanlines(60*8);
}
static int vga_set_mode(struct mode_info *mode)