On 2018-04-01 07:45 PM, Ilia Mirkin wrote: > 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). Building amdgpu into the kernel isn't feasible for a generic kernel such as a distro one, because it would require including all microcode into the kernel as well (12M right now, and growing). If a user decides to build amdgpu into their custom kernel and runs into trouble due to that, that's "doctor, it hurts if I do this" territory. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
