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I followed this how-to to get vgaswitcheroo working on my macbook 8,2: How to switch between Gfx cards on Macbook Pro 15" 8.2

I can boot directly from refind (bypassing grub); and I get X working with the radeon and keyboard OK. But I am unable to switch: I get a blank screen when I use vgaswitcheroo to switch to IGD. I can blindly switch back to DIS, and it works which means the laptop is not frozen. Any idea what causes that? I use kernel 3.8.0-19 generic from ubuntu 13.04. I also tried kernel vmlinuz-3.8.0-030800rc2-generic from the how-to bu no change.

By the way, I had to modprobe i915 to see the file vgaswitcheroo/switch. Is there anything else I have to do to get it work?

Thanks

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For the actual switch i have to shutdown X and do it from the console.

Also i've noticed that The blank screen issue I had (the screen seems to get completely shut off) issue seems to have some correlation to what GFX card you had running to in OSX before you reboot into Ubuntu.

Try installing gfxcardstatus in OSX and use the utility to set discrete or built in card in OSX then rebooting and trying the switch in Ubuntu.

  • Thanks for your answer. I tried using gfxcardstatus with both the intel and radeon cards, but it does not solve my problem: still a blank screen as you describe (the screen seems to get completely shut off). – seb007 Jun 3 '13 at 9:57
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This bug as been reported in the kernel bugzilla but so far no kernel develope has picked it up yet.

https://bugzilla.kernel.org/show_bug.cgi?id=56911

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Switching is still not working for me with latest kernel 3.11 rc5.

But it is now possible to boot with Radeon Dynamic Power management:

http://www.phoronix.com/scan.php?page=news_item&px=MTQyNDE

I tried on kernel 3.11 rc5, and it boots (directly from refind) with no more noisy fan or hot laptop. There are still problems (sometimes it refuses to boot, or does not wake up from suspend), but it's getting usable. Hopefully I will not need to switch to i915 if the Radeon is well supported!

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