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| author | Truxton Fulton <trux@truxton.com> | 2005-09-09 22:02:18 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-09 22:57:35 +0200 |
| commit | 59f4e7d572980a521b7bdba74ab71b21f5995538 (patch) | |
| tree | 65004b9875c8fa830de2879229ecf871de5525f4 /include | |
| parent | [PATCH] synclinkmp.c: fix async internal loopback (diff) | |
| download | linux-59f4e7d572980a521b7bdba74ab71b21f5995538.tar.xz linux-59f4e7d572980a521b7bdba74ab71b21f5995538.zip | |
[PATCH] fix reboot via keyboard controller reset
I have a system (Biostar IDEQ210M mini-pc with a VIA chipset) which will
not reboot unless a keyboard is plugged in to it. I have tried all
combinations of the kernel "reboot=x,y" flags to no avail. Rebooting by
any method will leave the system in a wedged state (at the "Restarting
system" message).
I finally tracked the problem down to the machine's refusal to fully reboot
unless the keyboard controller status register had bit 2 set. This is the
"System flag" which when set, indicates successful completion of the
keyboard controller self-test (Basic Assurance Test, BAT).
I suppose that something is trying to protect against sporadic reboots
unless the keyboard controller is in a good state (a keyboard is present),
but I need this machine to be headless.
I found that setting the system flag (via the command byte) before giving
the "pulse reset line" command will allow the reboot to proceed. The patch
is simple, and I think it should be fine for everybody whether they have
this type of machine or not. This affects the "hard" reboot (as done when
the kernel boot flags "reboot=c,h" are used).
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-i386/mach-default/mach_reboot.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/include/asm-i386/mach-default/mach_reboot.h b/include/asm-i386/mach-default/mach_reboot.h index 521e227db679..06ae4d81ba6a 100644 --- a/include/asm-i386/mach-default/mach_reboot.h +++ b/include/asm-i386/mach-default/mach_reboot.h @@ -22,7 +22,15 @@ static inline void mach_reboot(void) for (i = 0; i < 100; i++) { kb_wait(); udelay(50); - outb(0xfe, 0x64); /* pulse reset low */ + outb(0x60, 0x64); /* write Controller Command Byte */ + udelay(50); + kb_wait(); + udelay(50); + outb(0x14, 0x60); /* set "System flag" */ + udelay(50); + kb_wait(); + udelay(50); + outb(0xfe, 0x64); /* pulse reset low */ udelay(50); } } |