Revert f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip") from stable trees

Revert f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip") from stable trees

[Mika Westerberg]

Hi,

It seems that commit f5a26acf0162 ("pinctrl: intel: Initialize GPIO
properly when used through irqchip") can cause problems on some Skylake
systems with Sunrisepoint PCH-H. Namely on certain systems it may turn
the backlight PWM pin from native mode to GPIO which makes the screen
blank during boot.

There is more information here:

  https://bugzilla.redhat.com/show_bug.cgi?id=1543769

The actual reason is that GPIO numbering used in BIOS is using "Windows"
numbers meaning that they don't match the hardware 1:1 and because of
this a wrong pin (backlight PWM) is picked and switched to GPIO mode.

There is a proper fix for this but since it has quite many dependencies
on commits that cannot be considered stable material, I suggest we
revert commit f5a26acf0162 from stable trees 4.9, 4.14 and 4.15 to
prevent the backlight issue.

Thanks!

Re: Revert f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip") from stable trees

[Greg KH]

On Thu, Apr 26, 2018 at 03:53:02PM +0300, Mika Westerberg wrote:
> Hi,
> 
> It seems that commit f5a26acf0162 ("pinctrl: intel: Initialize GPIO
> properly when used through irqchip") can cause problems on some Skylake
> systems with Sunrisepoint PCH-H. Namely on certain systems it may turn
> the backlight PWM pin from native mode to GPIO which makes the screen
> blank during boot.
> 
> There is more information here:
> 
>   https://bugzilla.redhat.com/show_bug.cgi?id=1543769
> 
> The actual reason is that GPIO numbering used in BIOS is using "Windows"
> numbers meaning that they don't match the hardware 1:1 and because of
> this a wrong pin (backlight PWM) is picked and switched to GPIO mode.
> 
> There is a proper fix for this but since it has quite many dependencies
> on commits that cannot be considered stable material, I suggest we
> revert commit f5a26acf0162 from stable trees 4.9, 4.14 and 4.15 to
> prevent the backlight issue.

What is the "proper fix"?  Is it in Linus's tree yet?

thanks,

greg k-h

Re: Revert f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip") from stable trees

[Mika Westerberg]

On Thu, Apr 26, 2018 at 03:24:27PM +0200, Greg KH wrote:
> On Thu, Apr 26, 2018 at 03:53:02PM +0300, Mika Westerberg wrote:
> > Hi,
> > 
> > It seems that commit f5a26acf0162 ("pinctrl: intel: Initialize GPIO
> > properly when used through irqchip") can cause problems on some Skylake
> > systems with Sunrisepoint PCH-H. Namely on certain systems it may turn
> > the backlight PWM pin from native mode to GPIO which makes the screen
> > blank during boot.
> > 
> > There is more information here:
> > 
> >   https://bugzilla.redhat.com/show_bug.cgi?id=1543769
> > 
> > The actual reason is that GPIO numbering used in BIOS is using "Windows"
> > numbers meaning that they don't match the hardware 1:1 and because of
> > this a wrong pin (backlight PWM) is picked and switched to GPIO mode.
> > 
> > There is a proper fix for this but since it has quite many dependencies
> > on commits that cannot be considered stable material, I suggest we
> > revert commit f5a26acf0162 from stable trees 4.9, 4.14 and 4.15 to
> > prevent the backlight issue.
> 
> What is the "proper fix"?  Is it in Linus's tree yet?

This patch

  https://patchwork.ozlabs.org/patch/892813/

However, it is not yet in Linus' tree.

Re: Revert f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip") from stable trees

[Greg KH]

On Thu, Apr 26, 2018 at 04:36:23PM +0300, Mika Westerberg wrote:
> On Thu, Apr 26, 2018 at 03:24:27PM +0200, Greg KH wrote:
> > On Thu, Apr 26, 2018 at 03:53:02PM +0300, Mika Westerberg wrote:
> > > Hi,
> > > 
> > > It seems that commit f5a26acf0162 ("pinctrl: intel: Initialize GPIO
> > > properly when used through irqchip") can cause problems on some Skylake
> > > systems with Sunrisepoint PCH-H. Namely on certain systems it may turn
> > > the backlight PWM pin from native mode to GPIO which makes the screen
> > > blank during boot.
> > > 
> > > There is more information here:
> > > 
> > >   https://bugzilla.redhat.com/show_bug.cgi?id=1543769
> > > 
> > > The actual reason is that GPIO numbering used in BIOS is using "Windows"
> > > numbers meaning that they don't match the hardware 1:1 and because of
> > > this a wrong pin (backlight PWM) is picked and switched to GPIO mode.
> > > 
> > > There is a proper fix for this but since it has quite many dependencies
> > > on commits that cannot be considered stable material, I suggest we
> > > revert commit f5a26acf0162 from stable trees 4.9, 4.14 and 4.15 to
> > > prevent the backlight issue.
> > 
> > What is the "proper fix"?  Is it in Linus's tree yet?
> 
> This patch
> 
>   https://patchwork.ozlabs.org/patch/892813/
> 
> However, it is not yet in Linus' tree.

Ok, now reverted, thanks.

Oh, and 4.15.y is end-of-life, so nothing I can do there, sorry.

I pity anyone wanting to base a distro on that kernel, that would be
crazy... :)

thanks,

greg k-h