Hi,
I encountered the graphic corruption issue on IA64 machines by the
following operations.
0. enable VGA console(default setting). disable serial console setting.
1. boot the system at run level 3 and login via text-mode console
(/dev/tty1)
as the root user.
2. disable console blanking.
# setterm -blank 0
3. start X.
4. shutdown X.
5. start X again.
6. open the gnome-terminal and write someting to /dev/console.
# ls -l > /dev/console
The cause of this problem may be VGA console driver's misunderstanding
mode(text/graphic).
I confirmed this problem is fixed by the attached patch, but I don't
know this is the correct fix.
--------------------------------------------------------------------
VGA console driver can misunderstand the current mode(Text/Graphic) under
"disable console blanking" setting.
- start X
--> vt_ioctl() drivers/char/vt_ioctl.c
do_blank_screen(1) drivers/char/vt.c
sw->con_blank(vc_cons[currcons].d, 1, 0) drivers/char/vt.c
vgacon_blank() drivers/video/console/vgacon.c
vga_is_gfx = 1 /* enter Graphic mode */
- shutdown X
--> vt_ioctl()
do_unblank_screen(1) drivers/char/vt.c
sw->con_blank(vc_cons[currcons].d, 0, leaving_gfx)
vgacon_blank()
vga_is_gfx = 0 /* leave Graphic mode */
When "disable console blank" is set (=> blankinterval=0),
"do_unblank_screen()" function
returns without changing "blank_state", and when "blank_state" is
"blank_off",
"do_blank_screen() function returns without invoking sw->con_blank()
function.
That's why VGA console driver can misunderstand the current mode.
-----------------------------------------------------------------------
Regards,
Taku Izumi
Fix the graphic corruption issue on IA64 machines.
VGA console driver can misunderstand the current mode(Text/Graphic) under
"disable console blanking" setting. When "disable console blank" is set (blankinterval=0), "do_unblank_screen()" function returns without changing "blank_state", and when "blank_state" is "blank_off", "do_blank_screen() function returns without invoking sw->con_blank() function. That's why VGA console driver can misunderstand the current mode.
Signed-off-by: Nobuhiro Tachino <[email protected]>
Signed-off-by: Taku Izumi <[email protected]>
---
drivers/char/vt.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.21.5/drivers/char/vt.c
========================================================================
--- linux-2.6.21.5.org/drivers/char/vt.c 2007-06-13 12:03:11.000000000 +0900
+++ linux-2.6.21.5/drivers/char/vt.c 2007-06-13 12:07:48.000000000 +0900
@@ -3419,12 +3419,12 @@ void do_unblank_screen(int leaving_gfx)
return;
}
vc = vc_cons[fg_console].d;
+ blank_state = blank_normal_wait;
if (vc->vc_mode != KD_TEXT)
return; /* but leave console_blanked != 0 */
if (blankinterval) {
mod_timer(&console_timer, jiffies + blankinterval);
- blank_state = blank_normal_wait;
}
console_blanked = 0;
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