Arch Linux

trogdor1138

Member

From: The AWS cloud

Registered: 2012-12-19

Posts: 12

Website

Apple Radeon HD 6750M in EFI

I've successfully installed Arch under EFI on my MacBook Pro 8,2 (Early 2011). I've got GNOME up and running with 3D acceleration, and all works well. However, this laptop features hybrid Intel/ATI graphics. Everything that I've got running currently is on the integrated chip with the i915 module. Booting currently requires adding the following to GRUB:

outb 0x728 1
outb 0x710 2
outb 0x740 2
outb 0x750 0

These calls set the gmux switcher to output to the Intel chip and then turn off the AMD GPU. With the current kernel, that's all it takes; no kernel parameters required.

However, I can't for the life of me get output when I leave the ATI card enabled. It appears that the Radeon DRM module is unable to load a BIOS for the ATI GPU, as also seen in this thread: https://bbs.archlinux.org/viewtopic.php?id=151034

The DisplayPort output on this laptop requires use of the Radeon GPU, thus I am eager to get this working next on my install. Does anyone have this working, or can anyone provide pointers?

On a related note, the Fedora 18 beta live desktop boots fine without any register settings or kernel parameters. Once loaded, GNOME settings show that the Radeon is active and driving the display. I tried booting my kernel (stock Arch) from their GRUB, since they've made a lot of EFI-centric changes, but still ran into the same problem. I've also run a diff on their kernel config and the Arch one, but nothing jumps out at me. The only connected difference I could find is that on theirs the agp_intel module is integrated into the kernel, while Arch's is a module, which I have added to my initramfs.