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authorTruxton Fulton <trux@truxton.com>2005-09-09 13:02:18 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-09 13:57:35 -0700
commit59f4e7d572980a521b7bdba74ab71b21f5995538 (patch)
tree65004b9875c8fa830de2879229ecf871de5525f4
parent6e8dcee3e63f5a2cba4affff4bbb6e228f4b258a (diff)
[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>
-rw-r--r--include/asm-i386/mach-default/mach_reboot.h10
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 521e227db67..06ae4d81ba6 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);
}
}