Comment 17 for bug 1579374

Hi Andre,

I also have upgraded to 16.10, hoping for the bug to be fixed, as everything seemed to go smooth until kernel 4.7. However, I still got kernel panics.

In short, kernel 4.5 didn't have the bug: it was introduced by the backport Canonical made of amdgpu to 4.4. However the same bug, or a very similar one, was introduced as a regression in 4.8 (even vanilla 4.8).

However I found some workaround which prevents amdgpu from loading and crashing the system. Since then I lost the interest to make a patch to fix this: it's too much work to get only the Intel GPU working (the AMD GPU would not work anyway with the open drivers).

But it still would be nice if Ubuntu could ship with a kernel that doesn't crash on hardware that came with Ubuntu OEM (which, at least theoretically, should be tested by Canonical). If someone could go after this and fix the issue, it would be nice for the people who upgrade their Ubuntu OEM not to get an unusable system after reboot.

The workaround I'm currently using is as follows:

/etc/default/grub: Add amdgpu.runpm=0 to GRUB_CMDLINE_LINUX_DEFAULT

/etc/rc.local: Add the following command:

echo OFF > /sys/kernel/debug/vgaswitcheroo/switch

/etc/X11/xorg.conf: Create the file if it doesn't exist, and add the following in order to get the backlight controls working (otherwise it would be misdetected):

Section "Device"
    Identifier "Card0"
    Driver "intel"
    Option "Backlight" "intel_backlight"
EndSection