Arch Linux

garnerlogan65

Member

Registered: 2014-11-22

Posts: 26

Possible to disable discrete GPU on MacBook Pro?

Hey all, I have a Mid-2014 Retina MacBook Pro with dual GPUs. I've got most everything set up just right (enabled powersaving on CPU/IGPU, disabled bluetooth/webcam/sdcard, etc), as such I have switched from the NVIDIA graphics to Intel Iris Pro by chainloading the apple_set_os.efi patch through GRUB, removing the nvidia driver, and installing the Intel one. Now, I need to know if there is a way to completely power down the discrete GPU, acpi_call-git from the AUR does not work. Any ideas?

Thanks?

EDIT: I use gpu-switch, a utility for MacBooks that lets you specify which card you want to use on next boot. I am not sure whether this completely powers down the other card, I don't think it does since it still shows up in lspci and I still have bad battery drain. I will check vgaswitcheroo. I have the Intel GPU working, but I want to fully power down the other one to prevent battery drain.

Last edited by garnerlogan65 (2015-05-24 12:32:26)

SunBey

Member

Registered: 2015-05-17

Posts: 9

Re: Possible to disable discrete GPU on MacBook Pro?

Hy there,

you can try it with this entry (gfxcardstatus) in the wiki if and only if you have OS X on a bootable device!
https://wiki.archlinux.org/index.php/MacBookPro10,x

I did that on my MBP early 2011 with the defekt AMD / ATI card and it works great!

BUT ATTENTION you need the 2.2.1 Version of that program!!!!!
Earlyer or later versions WONT work!!!

Here you go: https://software.com/mac/apps/gfxcardstatus/2.2.1

Hope that helps in the first place (i know it is quick and dirty....but it works)

P.S. if you want t know the status of the GPU's you can do it with that :  cat /sys/kernel/debug/vgaswitcheroo/switch
comes from the ubuntu wiki: https://help.ubuntu.com/community/Hybri … switcheroo

Let us know how it works

SunBey

Last edited by SunBey (2015-05-24 09:19:48)

garnerlogan65

Member

Registered: 2014-11-22

Posts: 26

Re: Possible to disable discrete GPU on MacBook Pro?

SunBey, see first post for more information. I edited it.

SunBey

Member

Registered: 2015-05-17

Posts: 9

Re: Possible to disable discrete GPU on MacBook Pro?

Thats exactly what i did!
My AMD / ATI is fully powerd down!

So here comes what i did:
Boot the Mac into OS X (isn't important what version!) and install the gfxCardStatus 2.2.1 ..... fire it up.
Then put it to the INTEL grafikcard wait a moment and it shows that the INTEL GC is in use now.
Shutdown OS X and start up ARCH.

now copy this into your Terminal:  cat /sys/kernel/debug/vgaswitcheroo/switch
What does it show?

Mine shows that:

0:IGD:+:Pwr:0000:00:02.0
1:DIS: :Off:0000:01:00.0
2:DIS-Audio: :Off:0000:01:00.1

as you can see the "discrete" card (including whats with it-) is OFF!!

Try it and show us your results.

BTW my battery holds for 5 hours 24 minutes (with some minor tweaks )

garnerlogan65

Member

Registered: 2014-11-22

Posts: 26

Re: Possible to disable discrete GPU on MacBook Pro?

Huh, tried that too, didn't seem to work. Selecting the "Integrated Only" option and then rebooting into Arch, both cards are still powered on.

Here is the output of the command:

0:DIS-Audio: :Pwr:0000:01:00.1
1:IGD:+:Pwr:0000:00:02.0
2:DIS: :Pwr:0000:01:00.0

The only thing different is I use the apple_set_os patch as an .efi file, instead of needing grub to be patched, quicker and easier. It works just fine too. Shouldn't make a difference since my Intel GPU works under Linux. Not sure how to fix this though.

SunBey

Member

Registered: 2015-05-17

Posts: 9

Re: Possible to disable discrete GPU on MacBook Pro?

Okay i'am sorry that it wont work for you.

Did you tried "switcheroo" after you disable the discrete in OS X under Arch?
Maybee you can switch it now and disable it ...... reboot would be a nice idea

BTW if you use "lspci" again it will show you EVERYTHING again even if it disabled like mine because it asked for the REAL HW and the GC is still there

garnerlogan65

Member

Registered: 2014-11-22

Posts: 26

Re: Possible to disable discrete GPU on MacBook Pro?

It's fine. In theory, vgaswitcheroo should work. I just need to figure out how to get a script to run at bootup to disable the dedicated card and enable the integrated one. "echo OFF > /sys/kernel/debug/vgaswitcheroo/switch" should disable the nvidia card, and "echo IGD > /sys/kernel/debug/vgaswitcheroo/switch" should set the Intel GPU to work at boot. My /etc/rc.local file was empty, so I might find another way to get this to run.

Last edited by garnerlogan65 (2015-05-24 19:59:48)

SunBey

Member

Registered: 2015-05-17

Posts: 9

Re: Possible to disable discrete GPU on MacBook Pro?

To run this at startup make a "cron" job
do that with (in terminal) : crontab -e   
ATTENTION you have to do that with sudo!
Then put in :
@reboot echo OFF > /sys/kernel/debug/vgaswitcheroo/switch
@reboot echo IGD > /sys/kernel/debug/vgaswitcheroo/switch

exit and save the file and reboot.

voila your done

hope it works now!

garnerlogan65

Member

Registered: 2014-11-22

Posts: 26

Re: Possible to disable discrete GPU on MacBook Pro?

Thanks! Huh that didn't work either.

Last edited by garnerlogan65 (2015-05-24 20:57:55)