Bug 627372

Summary:	sys-kernel/gentoo-sources-4.9.34: Cpufreq broken after kernel upgrade from 4.9.16 to 4.9.34 (identical config)
Product:	Gentoo Linux	Reporter:	Jurgen <jurgen>
Component:	Current packages	Assignee:	Gentoo Kernel Bug Wranglers and Kernel Maintainers <kernel>
Status:	RESOLVED FIXED
Severity:	normal	CC:	hydrapolic
Priority:	Normal
Version:	unspecified
Hardware:	AMD64
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---
Attachments:	4.9.41 kernel -- cpufreq broken vanilla-sources 4.9.41 gentoo-sources 4.12.5

Description Jurgen 2017-08-09 07:20:33 UTC

Summary should be self-explanatory. After doing the upgrade, cpufreq no longer works (CPUs seem to be stuck in performance mode). Directory /sys/devices/system/cpu/cpufreq is empty. After rebooting into 4.9.16, everything is normal again (CPUs are using the ondemand governor, as specified).

Will happily provide any kind of log or system output. Am not doing that right now, because there is no compile error, dmesg is error-free, etc etc.

Comment 1 Tomáš Mózes 2017-08-09 16:32:32 UTC

Have you also tested the latest 4.9?

Comment 2 Jurgen 2017-08-11 08:25:23 UTC

Created attachment 488582 [details]
4.9.41 kernel -- cpufreq broken

Comment 3 Jurgen 2017-08-11 08:25:45 UTC

(In reply to Tomáš Mózes from comment #1)
> Have you also tested the latest 4.9?

Yep. Tested 4.9.41 (with the exact same .config file as the one I'm using for 4.9.16, in which cpufreq works just fine). With this latest kernel, cpufreq is broken as well (directory is empty, CPU running in apparent performance mode). See screenshot.

Comment 4 Tomáš Mózes 2017-08-11 10:36:23 UTC

Can you also test with vanilla sources? If it can be reproduced probably best is to report upstream.

Comment 5 Jurgen 2017-08-11 11:13:55 UTC

(In reply to Tomáš Mózes from comment #4)
> Can you also test with vanilla sources? If it can be reproduced probably
> best is to report upstream.

Just tested both vanilla 4.9.41 and the latest gentoo 4.5.12. Does NOT work in vanilla, but does work again in gentoo (see screenshots).

Comment 6 Jurgen 2017-08-11 11:14:30 UTC

Created attachment 488590 [details]
vanilla-sources 4.9.41

Comment 7 Jurgen 2017-08-11 11:15:05 UTC

Created attachment 488592 [details]
gentoo-sources 4.12.5

Comment 8 Tomáš Mózes 2017-08-11 12:57:42 UTC

Then it would be great to report at https://bugzilla.kernel.org. A git bisect would also speed it up I suppose.

Comment 9 Mike Pagano gentoo-dev

2018-07-31 14:27:28 UTC

Is this still an issue with more recent kernels?

Comment 10 Jurgen 2018-08-05 18:39:03 UTC

(In reply to Mike Pagano from comment #9)
> Is this still an issue with more recent kernels?

No. Haven't seen this bug anymore recently.

Comment 11 Mike Pagano gentoo-dev

2018-08-05 23:35:46 UTC

That's good news. Closing for now, feel free to comment or reopen if you see it again.