lkml.org 
[lkml]   [2005]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] : fix reboot via keyboard controller reset
Date
Hi,

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).

Here is a patch against include/asm-i386/mach-default/mach_reboot.h :

--- mach_reboot.h.orig 2005-08-22 22:23:13.000000000 -0700
+++ mach_reboot.h 2005-08-22 23:18:36.000000000 -0700
@@ -22,6 +22,14 @@
for (i = 0; i < 100; i++) {
kb_wait();
udelay(50);
+ 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);
}
Thanks,

-Truxton
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-08-23 08:41    [from the cache]
©2003-2011 Jasper Spaans