Re: [regression, bisected] Keyboard not responding after resuming from suspend/hibernate

From: Pavel Machek
Date: Sun Dec 02 2018 - 17:28:18 EST


On Fri 2018-11-30 15:44:55, Numan DemirdÃÄen wrote:
> Sun, 28 Oct 2018 22:06:54 +0300 tarihinde
> Numan DemirdÃÄen <if.gnu.linux@xxxxxxxxx> yazdÄ:
>
> >Thu, 25 Oct 2018 09:49:03 +0200 tarihinde
> >Pavel Machek <pavel@xxxxxx> yazdÄ:
> >
> >> Hi!
> >>
> >> Here's problem bisected down to:
> >>
> >> commit 9d659ae14b545c4296e812c70493bfdc999b5c1c
> >> Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> >> Date: Tue Aug 23 14:40:16 2016 +0200
> >>
> >> locking/mutex: Add lock handoff to avoid starvation
> >>
> >> Implement lock handoff to avoid lock starvation.
> >>
> >> Numan, I assume revert of that patch on the 4.18 kernel still makes
> >> it work?
> >>
> >
> >Unfortunately, I could not revert
> >9d659ae14b545c4296e812c70493bfdc999b5c1c on kernels from 4.18.16 to
> >4.10-rc1 because there were too much conflicts, which I could not solve
> >as an "average Joe". I tried a3ea3d9b865c2a8f7fe455c7fa26db4b6fd066e3
> >which is parent of 9d659ae14b545c4296e812c70493bfdc999b5c1c and
> >succeeded to compile kernel.
> >
> >git checkout a3ea3d9b865c2a8f7fe455c7fa26db4b6fd066e3
> >
> >Then, I compiled kernel and rebooted with it. I tried a couples of
> >times suspending and resuming, all of the time keyboard worked as
> >expected.
> >
>
> With this one line patch from Takashi Iwai, keyboard is working as
> expected after resuming from suspend/hibernate.
>
> --- a/kernel/locking/mutex.c
> +++ b/kernel/locking/mutex.c
> @@ -59,7 +59,7 @@ EXPORT_SYMBOL(__mutex_init);
> * Bit2 indicates handoff has been done and we're waiting for pickup.
> */
> #define MUTEX_FLAG_WAITERS 0x01
> -#define MUTEX_FLAG_HANDOFF 0x02
> +#define MUTEX_FLAG_HANDOFF 0x00
> #define MUTEX_FLAG_PICKUP 0x04
>
> #define MUTEX_FLAGS 0x07
>
>
> Thanks in advance and regards,

Ok. So it is a regression, and you can ask Linus to apply this
.. but... that's kind of heavy solution. Peter, do you have any other
ideas?

Pavel



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