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Re: [PATCH] input: i8042: add quirk to implement i8042 detect for AMD

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  Re: [PATCH] input: i8042: add quirk to implement i8042 detect for AMD Borislav Petkov <bp@alien8.de> - 2015-10-16 11:00 +0200
    Re: [PATCH] input: i8042: add quirk to implement i8042 detect for AMD Wan ZongShun <mcuos.com@gmail.com> - 2015-10-16 11:40 +0200
      Re: [PATCH] input: i8042: add quirk to implement i8042 detect for AMD Borislav Petkov <bp@alien8.de> - 2015-10-16 12:30 +0200
        Re: [PATCH] input: i8042: add quirk to implement i8042 detect for AMD Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-10-17 18:40 +0200

#1248486 — Re: [PATCH] input: i8042: add quirk to implement i8042 detect for AMD

On Fri, Oct 16, 2015 at 09:27:00AM -0400, Vincent Wan wrote:
> Detecting platform supports i8042 or not, AMD resorted to
> BIOS's FADT i8042 flag.
> 
> Signed-off-by: Vincent Wan <Vincent.Wan@amd.com>
> ---
>  drivers/input/serio/i8042-x86ia64io.h | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/input/serio/i8042-x86ia64io.h b/drivers/input/serio/i8042-x86ia64io.h
> index c115565..bf3a605 100644
> --- a/drivers/input/serio/i8042-x86ia64io.h
> +++ b/drivers/input/serio/i8042-x86ia64io.h
> @@ -9,6 +9,7 @@
>  
>  #ifdef CONFIG_X86
>  #include <asm/x86_init.h>
> +#include <linux/acpi.h>
>  #endif
>  
>  /*
> @@ -1047,6 +1048,11 @@ static int __init i8042_platform_init(void)
>  	/* Just return if pre-detection shows no i8042 controller exist */
>  	if (!x86_platform.i8042_detect())
>  		return -ENODEV;
> +
> +	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {

Why the vendor check if you're accessing a bit defined in the ACPI spec?

> +		if (!(acpi_gbl_FADT.boot_flags & ACPI_FADT_8042))
> +			return -ENODEV;
> +	}

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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#1248519

2015-10-16 16:58 GMT+08:00 Borislav Petkov <bp@alien8.de>:
> On Fri, Oct 16, 2015 at 09:27:00AM -0400, Vincent Wan wrote:
>> Detecting platform supports i8042 or not, AMD resorted to
>> BIOS's FADT i8042 flag.
>>
>> Signed-off-by: Vincent Wan <Vincent.Wan@amd.com>
>> ---
>>  drivers/input/serio/i8042-x86ia64io.h | 6 ++++++
>>  1 file changed, 6 insertions(+)

>>  /*
>> @@ -1047,6 +1048,11 @@ static int __init i8042_platform_init(void)
>>       /* Just return if pre-detection shows no i8042 controller exist */
>>       if (!x86_platform.i8042_detect())
>>               return -ENODEV;
>> +
>> +     if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
>
> Why the vendor check if you're accessing a bit defined in the ACPI spec?

From intel's 'x86_platform.i8042_detect' implementation, I doubt if
their BIOS is providing this i8024 flag.
So I have to implement my codes carefully.

>
>> +             if (!(acpi_gbl_FADT.boot_flags & ACPI_FADT_8042))
>> +                     return -ENODEV;
>> +     }
>
> --
> Regards/Gruss,
>     Boris.
>
> ECO tip #101: Trim your mails when you reply.



-- 
---
Vincent Wan(Zongshun)
www.mcuos.com
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#1248562

On Fri, Oct 16, 2015 at 05:35:40PM +0800, Wan ZongShun wrote:
> 2015-10-16 16:58 GMT+08:00 Borislav Petkov <bp@alien8.de>:
> > On Fri, Oct 16, 2015 at 09:27:00AM -0400, Vincent Wan wrote:
> >> Detecting platform supports i8042 or not, AMD resorted to
> >> BIOS's FADT i8042 flag.
> >>
> >> Signed-off-by: Vincent Wan <Vincent.Wan@amd.com>
> >> ---
> >>  drivers/input/serio/i8042-x86ia64io.h | 6 ++++++
> >>  1 file changed, 6 insertions(+)
> 
> >>  /*
> >> @@ -1047,6 +1048,11 @@ static int __init i8042_platform_init(void)
> >>       /* Just return if pre-detection shows no i8042 controller exist */
> >>       if (!x86_platform.i8042_detect())
> >>               return -ENODEV;
> >> +
> >> +     if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
> >
> > Why the vendor check if you're accessing a bit defined in the ACPI spec?
> 
> From intel's 'x86_platform.i8042_detect' implementation, I doubt if
> their BIOS is providing this i8024 flag.

Why would you doubt that - it is at least in ACPI v4, if not earlier. If
you still doubt that, go and check it or ask Intel people.

> So I have to implement my codes carefully.

What are you people talking about?!

It is in the ACPI spec - this bit is either set or not. If it is not
set, then that's a problem. But then it is the problem of this one BIOS.
Vendor checks have nothing to do in vendor-agnostic code.

Besides, there's intel_mid_i8042_detect() which is platform-specific and
Intel can supply a specific ->detect() function if, in the very distant
chance, they don't implement that bit.

Still no need for a vendor check!

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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#1249359

On Fri, Oct 16, 2015 at 12:21:55PM +0200, Borislav Petkov wrote:
> On Fri, Oct 16, 2015 at 05:35:40PM +0800, Wan ZongShun wrote:
> > 2015-10-16 16:58 GMT+08:00 Borislav Petkov <bp@alien8.de>:
> > > On Fri, Oct 16, 2015 at 09:27:00AM -0400, Vincent Wan wrote:
> > >> Detecting platform supports i8042 or not, AMD resorted to
> > >> BIOS's FADT i8042 flag.
> > >>
> > >> Signed-off-by: Vincent Wan <Vincent.Wan@amd.com>
> > >> ---
> > >>  drivers/input/serio/i8042-x86ia64io.h | 6 ++++++
> > >>  1 file changed, 6 insertions(+)
> > 
> > >>  /*
> > >> @@ -1047,6 +1048,11 @@ static int __init i8042_platform_init(void)
> > >>       /* Just return if pre-detection shows no i8042 controller exist */
> > >>       if (!x86_platform.i8042_detect())
> > >>               return -ENODEV;
> > >> +
> > >> +     if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
> > >
> > > Why the vendor check if you're accessing a bit defined in the ACPI spec?
> > 
> > From intel's 'x86_platform.i8042_detect' implementation, I doubt if
> > their BIOS is providing this i8024 flag.
> 
> Why would you doubt that - it is at least in ACPI v4, if not earlier. If
> you still doubt that, go and check it or ask Intel people.
> 
> > So I have to implement my codes carefully.
> 
> What are you people talking about?!
> 
> It is in the ACPI spec - this bit is either set or not. If it is not

Well, the fact that is is in a spec does not mean that vendors follow
it (and BTW I do not think that AMD as a CPU vendor can vouch for a
random notebook or desktop vendor that acquired and then hacked on some
version of some BIOS from some BIOS vendor so I agree that this check is
a no-go).

Historically we did not trust BIOS data with regard to i8042 on x86.
Maybe we should now using certain date cutoff (anything manufactured
past 201[2345?]).

Does Windows respect this flag? If it does then we could also trust it,
and not only on AMD but for all x86 CPUs.

Thanks.

-- 
Dmitry
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