# [SOLVED]: intel gpu: no powersaving mode RC6 after resume

## freifunk_connewitz

hi all

I'm posting this because there has been no improvement over two kernel generations.

after kernel 3.5.7, with gentoo-3.6.11, the powersaving function for the Intel GPU on my Intel i7-Notebook stops working after resume from suspend. this function, called RC6, just recently had been activated by default in the kernel and lets the GPU fall into idle mode if not needed, which saves a great amount of power. in practise: without rc6 the power consumption goes from 9 to ~17 W, the fan is running all the time and the battery lasts only half the time. annoying. you can check if the GPU actually uses RC6 by calling

```
cat /sys/kernel/debug/dri/0/i915_drpc_info  | grep residency
```

and check if the residency number is increasing. if not, RC6 is off.

however, after kernel 3.5.7, in my case with version 3.6.11, after resuming, RC6 seems to be off. also kernel 3.7.10 fails.

this is a known problem: https://bugzilla.kernel.org/show_bug.cgi?id=52411

my question: are the Gentoo maintainers aware of the bug, and do they have ways to advise the kernel guys of this, or did I oversee any other solution than skipping kernel upgrade after kernel upgrade in waiting for the bug to be solved?

my system (the working one):

3.5.7-gentoo #4 SMP Sat Jan 26 14:31:48 IST 2013 x86_64 Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz GenuineIntel GNU/Linux

x11-drivers/xf86-video-intel-2.21.4

(kernel option to activate RC not set, because default)

thank youLast edited by freifunk_connewitz on Fri Aug 30, 2013 9:42 am; edited 3 times in total

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## Hu

The commit referenced on the kernel bug you cited appears to have been included in Linux v3.8-rc5.  Does Linux v3.8.3 work correctly for you?

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## freifunk_connewitz

I never used a ~-kernel, but gave it a try after your suggestion. but: exactly same result with gentoo-sources-3.8.3-r1. RC6-residency after resume from suspend stuck at 32461, fan running constantly. so obviously also 3.8 is still affected.

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## toralf

FWIW there are few more bug reports at the kernel's bugzilla page regarding this issue (eg.: https://bugzilla.kernel.org/show_bug.cgi?id=48791)  - and this issue is still present in 3.8.3.

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## freifunk_connewitz

good news. seems to be solved for me with kernel gentoo-3.8.8.

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## freifunk_connewitz

reopen:

does occur again, but only randomly.

 after suspend-resume rc6 is not active, with kernel 3.8.13 /without any special rc6-settings on bootup.

boooh!

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## kernelOfTruth

please search for & file a bug report on:

https://bugs.freedesktop.org/

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## freifunk_connewitz

I wanted, but again, with kernel 3.10.7, the problem disappeared.

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