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.