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[PATCH] vgacon: no vertical resizing on EGA 

EGA boards suck: they mostly have write-only registers.  This is
particularly problematic for the overflow register: for being able to write
to it, we would have to handle vertical sync & such too, which (I'd say)
would potentially break a lot of configurations.  Instead, just disabling
vertical resize for EGA boards is just nice enough (horizontal resize still
works).

Fixes http://bugzilla.kernel.org/show_bug.cgi?id=6106

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Rafal Olearski <olearski@mail2.kim.net.pl>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Samuel Thibault 2006-02-24 13:03:59 -08:00 committed by Linus Torvalds
parent fe1db50c72
commit d1521260f5
1 changed files with 35 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

67
drivers/video/console/vgacon.c
View File

@ -509,57 +509,60 @@ static int vgacon_doresize(struct vc_data *c,
{
unsigned long flags;
unsigned int scanlines = height * c->vc_font.height;
u8 scanlines_lo, r7, vsync_end, mode, max_scan;
u8 scanlines_lo = 0, r7 = 0, vsync_end = 0, mode, max_scan;
spin_lock_irqsave(&vga_lock, flags);
outb_p(VGA_CRTC_MAX_SCAN, vga_video_port_reg);
max_scan = inb_p(vga_video_port_val);
if (max_scan & 0x80)
scanlines <<= 1;
vgacon_xres = width * VGA_FONTWIDTH;
vgacon_yres = height * c->vc_font.height;
outb_p(VGA_CRTC_MODE, vga_video_port_reg);
mode = inb_p(vga_video_port_val);
if (vga_video_type >= VIDEO_TYPE_VGAC) {
outb_p(VGA_CRTC_MAX_SCAN, vga_video_port_reg);
max_scan = inb_p(vga_video_port_val);
if (mode & 0x04)
scanlines >>= 1;
if (max_scan & 0x80)
scanlines <<= 1;
scanlines -= 1;
scanlines_lo = scanlines & 0xff;
outb_p(VGA_CRTC_MODE, vga_video_port_reg);
mode = inb_p(vga_video_port_val);
outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
r7 = inb_p(vga_video_port_val) & ~0x42;
if (mode & 0x04)
scanlines >>= 1;
if (scanlines & 0x100)
r7 |= 0x02;
if (scanlines & 0x200)
r7 |= 0x40;
scanlines -= 1;
scanlines_lo = scanlines & 0xff;
/* deprotect registers */
outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
vsync_end = inb_p(vga_video_port_val);
outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
outb_p(vsync_end & ~0x80, vga_video_port_val);
outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
r7 = inb_p(vga_video_port_val) & ~0x42;
if (scanlines & 0x100)
r7 |= 0x02;
if (scanlines & 0x200)
r7 |= 0x40;
/* deprotect registers */
outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
vsync_end = inb_p(vga_video_port_val);
outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
outb_p(vsync_end & ~0x80, vga_video_port_val);
}
outb_p(VGA_CRTC_H_DISP, vga_video_port_reg);
outb_p(width - 1, vga_video_port_val);
outb_p(VGA_CRTC_OFFSET, vga_video_port_reg);
outb_p(width >> 1, vga_video_port_val);
outb_p(VGA_CRTC_V_DISP_END, vga_video_port_reg);
outb_p(scanlines_lo, vga_video_port_val);
outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
outb_p(r7,vga_video_port_val);
if (vga_video_type >= VIDEO_TYPE_VGAC) {
outb_p(VGA_CRTC_V_DISP_END, vga_video_port_reg);
outb_p(scanlines_lo, vga_video_port_val);
outb_p(VGA_CRTC_OVERFLOW, vga_video_port_reg);
outb_p(r7,vga_video_port_val);
/* reprotect registers */
outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
outb_p(vsync_end, vga_video_port_val);
/* reprotect registers */
outb_p(VGA_CRTC_V_SYNC_END, vga_video_port_reg);
outb_p(vsync_end, vga_video_port_val);
}
spin_unlock_irqrestore(&vga_lock, flags);
return 0;
}