Re: Regression in 4.8 - CPU speed set very low
From: Srinivas Pandruvada
Date: Thu Sep 29 2016 - 11:59:07 EST
On Thu, 2016-09-29 at 14:19 +0200, Rafael J. Wysocki wrote:
> > My laptop was inadvertently put to sleep while I was gone. I forgot
> > to leave aÂ
> > note for my wife and she quieted the noisy cpu fan. :)
> It looks like in 4.8-rc we made a change that caused the "high" trip
> point to
> be acted on.
This high trip point we don't expose in thermal subsystem (the thermal
Âzone dump didn't show this anywhere as a trip). This is exposed by
core-dts driver only. This is the point BIOS is supposed to act, I
guess that's why you are seeing 50% clock modulation.Â
Are you running thermaldÂ
# ps -e | grep thermald
> Srinivas, Rui, do you recall what that can be?
> One more question (I think I asked it previously): In the failing
> (4.8-rc1 and later), when the frequency drops down to the 400 MHz,
> does it
> ever go back higher or is it stuck at that level forever?
> In any case, it may help to file a bug at bugzilla.kernel.org against
> CPU/thermal or similar and let me know the bug number.ÂÂWe'll need to
> collect some tracepoint data to debug this and some place to put them
> into for easy reference.
Yes, this is good idea.