[PATCH] kexec: x86: i8259 shutdown: disable interrupts

From: Eric W. Biederman <ebiederm@xmission.com>

This patch disables interrupt generation from the legacy pic on reboot.  Now
that there is a sys_device class it should not be called while drivers are
still using interrupts.

There is a report about this breaking ACPI power off on some systems.
http://bugme.osdl.org/show_bug.cgi?id=4041
However the final comment seems to exonerate this code.  So until
I get more information I believe that was a false positive.

Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/i386/kernel/i8259.c b/arch/i386/kernel/i8259.c
index 2c4813b47e57..178f4e9bac9d 100644
--- a/arch/i386/kernel/i8259.c
+++ b/arch/i386/kernel/i8259.c
@@ -268,10 +268,22 @@ static int i8259A_suspend(struct sys_device *dev, pm_message_t state)
         return 0;
 }
 
+static int i8259A_shutdown(struct sys_device *dev)
+{
+        /* Put the i8259A into a quiescent state that
+         * the kernel initialization code can get it
+         * out of.
+         */
+        outb(0xff, 0x21);       /* mask all of 8259A-1 */
+        outb(0xff, 0xA1);       /* mask all of 8259A-1 */
+        return 0;
+}
+
 static struct sysdev_class i8259_sysdev_class = {
         set_kset_name("i8259"),
         .suspend = i8259A_suspend,
         .resume = i8259A_resume,
+        .shutdown = i8259A_shutdown,
 };
 
 static struct sys_device device_i8259A = {