Talk:MacBookPro8,x

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Obsolete information about kernel params

The 8,2/8,3 section mentions having to pass specific kernel parameters but according to this bug report that should no longer be needed --Madpet (talk) 12:58, 20 July 2020 (UTC)Reply[reply]

Alright, I just tried installing Arch on a completely wiped Macbook8,2 (Early 2011 model), and the only kernel parameter that needed to be added for things to work correctly was `radeon.modeset=0` (if not added, the screen freezes during boot). All the other stuff seems to be obsolete - the page could do with a cleanup. --Madpet (talk) 16:19, 20 July 2020 (UTC)Reply[reply]
The 8,1 section mentions "i915.enable_fbc=1 usbcore.autosuspend=1 h". Is the space between "1" and "h" an accident? Is the sole "h" a typo? I can't find anything about a kernel parameter that's just "h". ThermonuclearWarthog (talk) 20:53, 22 January 2021 (UTC)Reply[reply]
In recent kernels, it seems that Hybrid Graphics are mostly working on my Macbook8,2 using rEFInd as the boot mechanism. Frozen screen during boot was due to a few interrelated items (1) The AMD HD6490M was set as the primary card upon boot, and (2) the driver wasn't loading properly.
  • Solution for (1) - to set the Intel i915 card as primary, there are two ways
    • boot Arch into low-graphics mode using i915.modeset=0 radeon.modeset=0 kernel parameters (I used TTY console), and run:
      chattr -i /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
      printf '\x07\x00\x00\x00\x01\x00\x00\x00' > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
      chattr +i /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
    • (untested) boot OSX and use root to run nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00
  • Solution for (2) - to ensure the right driver is loading properly:
    • Ensure that /etc/modprobe.d/blacklist contains blacklist amdgpu (and NOT blacklist radeon). The AMD HD6490M doesn't seem to be supported by the amdgpu module.
    • Ensure that linux-firmware package is installed (else you get an error in dmesg about inability to find radeon/CAICOS_pfp.bin)
Note that you can set the AMD HD6490M card as the default during boot by using a similar printf to the efivar as above, but using the values \x07\x00\x00\x00\x00\x00\x00\x00 (notice the 5th byte as 0 rather than 1).
I've been able to successfully boot into both the radeon and the i915 cards using a combination of the above methods.
Separately, the vga-switcheroo starts the gmux with both of these cards powered on. This can confuse sway's output auto-detect magic, noting that there are 2 LVDS screens and try to extend across them. Turning off the inactive card BEFORE starting sway will alleviate the problem. Turning off the inactive card after it's already being referenced led me to a hanging system. This can be accomplished using vga-switcheroo --Wassy121 (talk) 05:11, 9 August 2022 (UTC)Reply[reply]