Re: [PATCH v4] 8042: Enable A20 using KBC to fix S3 resume on someMSI laptops

[Dmitry Torokhov]

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@xxxxxxxxxxxxxxxxxxxx>
> > ---
> >  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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