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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>
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@ -921,6 +921,7 @@ static int __init i8042_platform_init(void)
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int retval;
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#ifdef CONFIG_X86
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u8 a20_on = 0xdf;
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/* Just return if pre-detection shows no i8042 controller exist */
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if (!x86_platform.i8042_detect())
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return -ENODEV;
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@ -960,6 +961,14 @@ static int __init i8042_platform_init(void)
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if (dmi_check_system(i8042_dmi_dritek_table))
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i8042_dritek = true;
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/*
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* A20 was already enabled during early kernel init. But some buggy
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* BIOSes (in MSI Laptops) require A20 to be enabled using 8042 to
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* resume from S3. So we do it here and hope that nothing breaks.
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*/
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i8042_command(&a20_on, 0x10d1);
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i8042_command(NULL, 0x00ff); /* Null command for SMM firmware */
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#endif /* CONFIG_X86 */
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return retval;
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