646043 - Hardware acceleration seems to require discrete GPU on Macs with two GPUs

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Anthony Ricaud (:rik)]

I've seen several user reports [1] saying that opening Firefox 4 enables the discrete GPU. While it may improve performance, it's also consuming a lot more battery than the integrated GPU.

I believe this is automatically done by OS X when doing some OpenGL calls. Maybe there is a way to disable the automatic switching?

[1] One report in French http://forum.macbidouille.com/index.php?s=&showtopic=222018&view=findpost&p=3414014

Comment 1

[Benoit Jacob [:bjacob] (mostly away)]

I've heard about that too. The on-board low-power GPU should be powerful enough for Layers acceleration so it is really unwanted behavior on the part of the OS that it enables the discrete GPU for that.

Does Core GL (CGL) provide some API to say 'hello, no need to enable the GPU for these OpenGL calls' ?

Comment 2

[Anthony Ricaud (:rik)]

I've found this app that lets users select the GPU they want : https://github.com/codykrieger/gfxCardStatus

So somewhere in the code, there might be something to stay on the integrated GPU. Although I guess it is a system-wide force switch where we only want to say "Firefox doesn't need the integrated GPU"

Comment 3

[Boris Zbarsky [:bzbarsky]]

Do we have Apple contacts we could ask about this?

Comment 4

[Benoit Jacob [:bjacob] (mostly away)]

CC'ing Chris Marrin at Apple.

Comment 5

[Jeff Muizelaar [:jrmuizel]]

We cause the use of the external GPU by calling code that does something like the following:

IOServiceGetMatchingServices(kIOMasterPortDefault, IOServiceMatching("AppleGraphicsControl"), &iterator);
service = IOIteratorNext(iterator);
/* passing 1 instead of 0 causes the external GPU to be used */
IOServiceOpen(service, mach_task_self(), 1, &switcherConnect);


I don't know why Safari gets a 0 and we get a 1.

Comment 6

[Jeff Muizelaar [:jrmuizel]]

The WWDC 2011 slide suggest information about this:

 Pixel Format must track multiple GPUs
■ CGLFPAAllowOfflineRenderer • Supporting Integrated GPUs
■ Add Info.plist attribute NSSupportsAutomaticGraphicsSwitching = YES

Comment 7

[Jeff Muizelaar [:jrmuizel]]

I quickly tried using NSOpenGLPFAAllowOfflineRenderers and couldn't get it to work. Safari does use NSOpenGLPFAAllowOfflineRenderers.

Comment 8

[Anthony Ricaud (:rik)]

I've found this technical note: http://developer.apple.com/library/mac/#technotes/tn2229/_index.html

Also, maybe checkout a 2010 session called "Taking Advantage of Multiple GPUs" http://developer.apple.com/videos/wwdc/2010/

Comment 9

[Jesse Ruderman]

Dup of bug 604135?

Comment 11

[Jeff Muizelaar [:jrmuizel]]

This should be resolved on Nightly running on 10.7. Is it working properly?

Comment 12

[Travis Tabbal]

Nightly downloaded 10/28/2011 seems to be working properly on 10.7.2 MBP early 2011. gfxCardStatus app set to Dynamic Switching, shows integrated GPU enabled with the Nightly running. Running FF7 release causes discrete GPU to enable under the same setup. Thanks for fixing this, it's nice to be able to leave it on dynamic.