Revert f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip") from stable trees
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!
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
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.
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
linux-stable-mirror@lists.linaro.org
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Greg KH -
Mika Westerberg