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!