Arch Linux

halogene

Member

Registered: 2013-05-29

Posts: 69

MacBook Pro 8,2 bricked radeon/i915 even outside linux

My hardware:

MacBook Pro 8,2
core i7, 8GB Ram, Radeon HD 6400M Series GPU, 1680x1050 non-glare screen

After having done a lot of reading, I tried to install Arch Linux onto my MacBook Pro. I re-installed MacOS, did all updates, and followed the wiki instructions. After a couple of failed attempts to get GRUB to EFI-boot from the Apple bootloader (carefully avoiding the usage of efibootmgr), I finally managed to EFI-boot the base system via reFind and EFISTUB. I quickly was able to set up everything I need, only X would work only with the radeon driver. But since I went through all the trouble to EFI-boot the machine solely for the purpose of being able to use the i915 graphics, I tried all the kernel paramters (radeon.modeset=0 and all the i915 parameters that are mentioned all over the places in all sorts of recommended/mentioned combinations). But no luck, startx would always exit with a "no screens found" message when configuring xorg.conf to use the "intel" driver. Needless to say, both xf86-video-radeon and xf86-video-intel were installed. Using the module acpi_call and doing "sudo turn_off_gpu.sh" ends up with "failed" messages only. Doing "lspci | grep VGA" returns both intel and AMD graphics adapter, so I should actually have successfully booted in EFI mode. I started blacklisting the radeon module, but lspci -k still shows the radeon module for the gpu. The only thing I did not try is adding the "outb" lines to GRUB as I'm not using GRUB and was very reluctant to change anything about my working EFI boot setup. Finally, I decided to try vgaswitcheroo. I read that I need to enable debugfs in the fstab before, so I added the line "debugfs /sys/kernel/debug debugfs 0 0" to fstab. Careful as I am, I rebooted before installing vgaswitcheroo.

And from then on, arch linux boots into a black screen. I can log in if I switch to tty1 or another and type blind, and I can reboot that way. Just as a routine, I try to boot up MacOS, and it also boots into a black screen. This has always worked so far, I tried that regularly. I totally panick and grab an Ubuntu 12.04 CD that happens to lie around and boot it via the apple bootloader in bios compatibility mode (which worked, before, too). It also boots into black screen. Even the darn MacOS Install DVD boots into a black scren now!

But I'm not the one that gives up easily. Since Arch displays all the boot messages until it loads the virtual console (I think), I messed around with the kernel parameters again and it turns out I can get to console login if I use radeon.modeset=0. I configured X to use the fbdev driver again, and there you go, I get graphical login and whatnot with radeon.modeset=0. Still, even though fbdev is used, the temperature is around 70 to 80 degrees Celsius. I decide to finally install vgaswitcheroo (systemd-vgaswitcheroo-units), since the whole thing is bricked anyway, and enable it via systemd. Radeon module is blacklisted. I still am only able to reach graphical or console target when radeon.modeset=0 is set, but now I got a X running with desktop effects on fbdev driver and around 50 degrees Ceslius temperature. Still, every other OS boots into black screen.

I seem to have completely messed up everything. Strangely enough, the arch system seems to be completely usable (except that it wakes up from suspend with that black screen now), but it seems to be the only system that can be run on that machine now. I would greatly appreciate any help on what might have gone wrong or what I could try to enable the gpu for other systems again.

Edit: I seem to have managed to brick reFind now, too. While trying to boot the MacOS Installation medium it seems to have magically "fixed" the EFI partition leaving me with no reFind at all now. There's no way I can access that stupid thing anymore. Gotta send it in, probably (

Last edited by halogene (2013-05-29 15:57:58)

halogene

Member

Registered: 2013-05-29

Posts: 69

Re: MacBook Pro 8,2 bricked radeon/i915 even outside linux

I'm still reluctant to give up on that bricked machine... Since it is able to display part of the boot up messages of the arch install cd and the previously working installation showed everything until loading of the virtual console (at least that's what I believe it did when the screen went black), it looks to me that the problem lies in initializing a different graphical output. That would also explain why I was able to initialize X only with the fbdev driver... and the screen didn't flicker during boot-up when I did radeon.modeset=0 so I assume it stayed on framebuffer mode all along.

Does anyone know of a boot medium that boots into framebuffer video mode even though a GPU is present? All I'd need is a bash or similar shell. I can load into the UEFI shell with arch install CD, but I'm not familiar with that shell and it follows a different syntax than I am used to, as it is designed for an entirely different purpose. If anyone knows a boot medium that does not try to pipe the graphical output through the gpu (or the integrated i915 graphics). Must be something like this around?

Last edited by halogene (2013-05-31 08:16:13)

halogene

Member

Registered: 2013-05-29

Posts: 69

Re: MacBook Pro 8,2 bricked radeon/i915 even outside linux

...and now I received the hint to reset NVRAM with doing a weird key combo during startup, and the screen does not even give me light during the bootup anymore. Case closed, move on, nothing to see here.

Last edited by halogene (2013-05-31 09:13:11)

MilenKid

Member

Registered: 2013-04-21

Posts: 86

Re: MacBook Pro 8,2 bricked radeon/i915 even outside linux

Hello,
My system, not MacBook, has Intel i915 + Radeo HD hybrid graphics.
With VGA switcheroo every time I switch to Radeon screen goes blind. I've tried DIS, DDIS
I think it's simply not meant to work.
Difference is that mine fixes itself (switches to Intel) after restart. Maybe yours keep the setting remembered and that's why you go blind?
I have no ideea how to make this to work. What's really strange is that it worked in Ubuntu 9 or 10.