On Sun, Apr 1, 2018 at 1:39 PM, Christian König <christian.koenig at amd.com> wrote: > Am 30.03.2018 um 22:45 schrieb Takashi Iwai: >> >> amdgpu driver lacks of modeset module option other drm drivers provide >> for enforcing or disabling the driver load. Interestingly, the >> amdgpu_mode variable declaration is already found in the header file, >> but the actual implementation seems to have been forgotten. >> >> This patch adds the missing piece. > > > NAK, modesetting is mandatory for amdgpu and we should probably remove the > option to disable it from other DRM drivers without UMS support as well > (pretty much all of them now). > > If you want to prevent a driver from loading I think the correct way to do > so is to give modprobe.blacklist=amdgpu on the kernel commandline. > > That would remove the possibility to prevent the driver from loading when it > is compiled in, but I don't see much of a problem with that. Having a way to kill the graphics driver is a very useful debugging tool, and also a quick and easy way to get out of an unpleasant situation where graphics are messed up / system hangs / etc. The modprobe blacklist kernel arg only works in certain environments (and only if it's a module). Every other DRM driver has this and this is a well-documented workaround for "graphics are messed up when I install linux", why not allow a uniform experience for the end users who are just trying to get their systems up and running? -ilia
