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SubjectRe: [PATCH v4] 8042: Enable A20 using KBC to fix S3 resume on some MSI laptops
On Tue, Dec 11, 2012 at 04:45:31PM -0800, H. Peter Anvin wrote:
> Looks good to me. Alan/Rafael/Dmitry, OK for me to commit this?

Sure. I hope it won't affect other boxes, otherwise more DMI tables
will be needed.

Thanks.

>
> -hpa
>
> On 12/11/2012 01:18 PM, Ondrej Zary wrote:
> > 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>
> > ---
> > drivers/input/serio/i8042-x86ia64io.h | 9 +++++++++
> > 1 files changed, 9 insertions(+), 0 deletions(-)
> >
> > 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;
> >
>

--
Dmitry


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