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#1 2012-11-23 06:07:20

eruditorum
Member
Registered: 2012-11-12
Posts: 130

[SOLVED] Force GPU powersaving in ACTIVE state

Hello to everyone!

GPU on my system is Intel HD 3000 and in Windows there was a switch in Intel HD Graphics Control Panel (this is a standart GUI tool for the "card" from vendor), and when you turn it on it really saves battery.

But is there such setting for [Arch]Linux? Which kernel parameter?

And no, I am not talking about powersaving in idle mode, but about economy when adapter is in ACTIVE state:
RC6[p|pp] - GPU enters these states when idle, but still works at full power when active.

Also, I don't really see any difference in all those idle states - all seem to give equal effect. But forcing ASPM with "pcie_aspm=force" in kernel line only increases power consumption.

Thanks in advance for help and sorry for awful english.

Last edited by eruditorum (2013-02-16 11:06:12)

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#2 2012-11-23 06:50:37

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: [SOLVED] Force GPU powersaving in ACTIVE state

$ modinfo i915 | grep parm 

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#3 2012-11-23 07:52:37

eruditorum
Member
Registered: 2012-11-12
Posts: 130

Re: [SOLVED] Force GPU powersaving in ACTIVE state

As for powersaving these options exist:

powersave:Enable powersavings, fbc, downclocking, etc. (default: true) (int)
i915_enable_rc6:Enable power-saving render C-state 6. Different stages can be selected via bitmask values (0 = disable; 1 = enable rc6; 2 = enable deep rc6; 4 = enable deepest rc6). For example, 3 would enable rc6 and deep rc6, and 7 would enable everything. default: -1 (use per-chip default) (int)
i915_enable_fbc:Enable frame buffer compression for power savings (default: -1 (use per-chip default)) (int)
lvds_downclock:Use panel (LVDS/eDP) downclocking for power savings (default: false) (int)

All powersaving is enabled by default as I see, so there is no need to set the last two.
But again all this is about powersaving in IDLE mode (maybe except "i915_enable_fbc" and "lvds_downclock" options).
So GPU cannot be forced to use low power in ACTIVE state as I see it. sad

Last edited by eruditorum (2012-11-24 04:23:20)

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#4 2013-02-13 10:42:58

eruditorum
Member
Registered: 2012-11-12
Posts: 130

Re: [SOLVED] Force GPU powersaving in ACTIVE state

Finally, I've been walking in /sys with udevadm and found this on the internets: http://lists.freedesktop.org/archives/i … 20348.html

So I can set frequencies in /sys/class/drm/card0/gt_{min,max}_freq_mhz files.
For example force minimum frequency when AC is unplugged, and restore back to maximum on AC.

It seems that this is exactly what I've been looking for.

Last edited by eruditorum (2013-02-13 11:03:40)

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