i386: fix machine rebooting

Commit 59f4e7d572980a521b7bdba74ab71b21f5995538 fixed machine rebooting
on Truxton's machine (when no keyboard was present).  But it broke it on
Lee's machine.

The patch reinstates the old (pre-59f4e7d572980a521b7bdba74ab71b21f5995538)
code and if that doesn't work out, try the new,
post-59f4e7d572980a521b7bdba74ab71b21f5995538 code instead.

Cc: Lee Garrett <lee-in-berlin@web.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 24 insertions, 1 deletions

diff --git a/include/asm-i386/mach-default/mach_reboot.h b/include/asm-i386/mach-default/mach_reboot.h
index a955e57ad016..e23fd9fbebb3 100644
--- a/include/asm-i386/mach-default/mach_reboot.h
+++ b/include/asm-i386/mach-default/mach_reboot.h
@@ -19,14 +19,37 @@ static inline void kb_wait(void)
 static inline void mach_reboot(void)
 {
         int i;
+
+        /* old method, works on most machines */
         for (i = 0; i < 10; i++) {
                 kb_wait();
                 udelay(50);
+                outb(0xfe, 0x64);       /* pulse reset low */
+                udelay(50);
+        }
+
+        /* New method: sets the "System flag" which, when set, indicates
+         * successful completion of the keyboard controller self-test (Basic
+         * Assurance Test, BAT).  This is needed for some machines with no
+         * keyboard plugged in.  This read-modify-write sequence sets only the
+         * system flag
+         */
+        for (i = 0; i < 10; i++) {
+                int cmd;
+
+                outb(0x20, 0x64);       /* read Controller Command Byte */
+                udelay(50);
+                kb_wait();
+                udelay(50);
+                cmd = inb(0x60);
+                udelay(50);
+                kb_wait();
+                udelay(50);
                 outb(0x60, 0x64);       /* write Controller Command Byte */
                 udelay(50);
                 kb_wait();
                 udelay(50);
-                outb(0x14, 0x60);       /* set "System flag" */
+                outb(cmd | 0x04, 0x60); /* set "System flag" */
                 udelay(50);
                 kb_wait();
                 udelay(50);