Re: [PATCH] drivers:gpu:vga_switcheroo: Work around dramatic power drain in laptops

[Uwe Bonnes]

Alexander Tarasikov <alexander.tarasikov@xxxxxxxxx> wrote:
> 2012/4/29 Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>:
> > The module parameter is probably the wrong long term option. Do you know
> > if the problem is general or specific to some laptops. If it's the latter
> > then it might also be worth implementing a DMI and/or PCI detection
> > routine to match the laptops you know are afflicted and automatically
> > enabled it.
> > Alan

> I agree that module parameter is not a good idea, but I have seen a
> lot of reports of the problem and no patches were proposed, 
> so I tried to do what I could. It
> could be a good temporary solution until we make sure it does not break
> any configurations. I am unsure how muxless/muxed cards may differ in
> behaviour.

> I suspect that the problem is specific to all laptops with
> intel+radeon combination.

Intel+Nvidia combination seems to be affected too!

> So far I have found these reports of radeon eating battery

> [2010] Acer TravelMate Timeline 8371
> [2012] Hp Envy 14 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/909337
> [2012] Thinkpad T400 https://bbs.archlinux.org/viewtopic.php?id=133329
> [2012] Sony Vaio SE15 (VPCSE1v9E)
> http://blog.ejbca.org/2012/02/ubuntu-gnulinux-1204-precise-on-sony.html

I can confirm the problem with an intel+nvidia combination, on a Thinkpad T520:
> lspci |grep -i VGA
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core \
Processor Family Integrated Graphics Controller (rev 09)
01:00.0 VGA compatible controller: nVidia Corporation GF119 [Quadro NVS 4200M] (rev ff)

I suspend with "DIS"cret graphics off. Resuming comes up with about 5 Watt
more power drain compared before suspend. Switching "DIS" needs another 5
Watt. Switching "DIS" off again brings me back to the power drain level
before suspend.

I vote for Alexander proposal!

Bye

-- 
Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------

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