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Subject[tip:x86/urgent] x86, 8042: Enable A20 using KBC to fix S3 resume on some MSI laptops
Commit-ID:  ad68652412276f68ad4fe3e1ecf5ee6880876783
Gitweb: http://git.kernel.org/tip/ad68652412276f68ad4fe3e1ecf5ee6880876783
Author: Ondrej Zary <linux@rainbow-software.org>
AuthorDate: Tue, 11 Dec 2012 22:18:05 +0100
Committer: H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 11 Dec 2012 14:55:16 -0800

x86, 8042: Enable A20 using KBC to fix S3 resume on some MSI laptops

Some MSI laptop BIOSes are broken - INT 15h code uses port 92h to enable A20
line but resume code assumes that KBC was used.
The laptop will not resume from S3 otherwise but powers off after a while
and then powers on again stuck with a blank screen.

Fix it by enabling A20 using KBC in i8042_platform_init for x86.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=12878

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/201212112218.06551.linux@rainbow-software.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
drivers/input/serio/i8042-x86ia64io.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/input/serio/i8042-x86ia64io.h b/drivers/input/serio/i8042-x86ia64io.h
index d6cc77a..5f306f7 100644
--- a/drivers/input/serio/i8042-x86ia64io.h
+++ b/drivers/input/serio/i8042-x86ia64io.h
@@ -921,6 +921,7 @@ static int __init i8042_platform_init(void)
int retval;

#ifdef CONFIG_X86
+ u8 a20_on = 0xdf;
/* Just return if pre-detection shows no i8042 controller exist */
if (!x86_platform.i8042_detect())
return -ENODEV;
@@ -960,6 +961,14 @@ static int __init i8042_platform_init(void)

if (dmi_check_system(i8042_dmi_dritek_table))
i8042_dritek = true;
+
+ /*
+ * A20 was already enabled during early kernel init. But some buggy
+ * BIOSes (in MSI Laptops) require A20 to be enabled using 8042 to
+ * resume from S3. So we do it here and hope that nothing breaks.
+ */
+ i8042_command(&a20_on, 0x10d1);
+ i8042_command(NULL, 0x00ff); /* Null command for SMM firmware */
#endif /* CONFIG_X86 */

return retval;

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