On 20/01/17 04:35 AM, Nils Holland wrote: > Hi folks, > > there seems to be an issue on 32 bit kernels which makes graphics > output look all messed up under X when using the amdgpu drm kernel > driver. > > In fact, the same issue was present at some time in 2015 using the > radeon driver too, but it has been fixed a long time ago, as can be > seen here: > > https://bugs.freedesktop.org/show_bug.cgi?id=84627#c35 > > Now, I reported the same issue in conjunction with the amdgpu driver > back when I first noticed it back then. Nothing has happened since > then, but my bug report can still be found here: > > https://bugs.freedesktop.org/show_bug.cgi?id=91831 > > Personally, I had been using the (working) radeon driver again, and > only today I decided to check if the issue in amdgpu still exists. And > yes, it seems so: I still get garbled output when using a current > kernel with a current version of the amdgpu driver. > > Now, I've tried to just "port" the fix that had been done to the radeon > driver in 2015 (see the first link above) to the amdgpu driver and created > myself the following little patch: > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c 2016-12-11 20:17:54.000000000 +0100 > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c 2017-01-19 15:38:56.972034489 +0100 > @@ -372,6 +372,10 @@ > if (!drm_arch_can_wc_memory()) > bo->flags &= ~AMDGPU_GEM_CREATE_CPU_GTT_USWC; > > + #ifdef CONFIG_X86_32 > + bo->flags &= ~AMDGPU_GEM_CREATE_CPU_GTT_USWC; > + #endif > + > amdgpu_fill_placement_to_bo(bo, placement); > /* Kernel allocation are uninterruptible */ > r = ttm_bo_init(&adev->mman.bdev, &bo->tbo, size, type, The corresponding code in the radeon driver has changed quite a bit since this original fix. It would be better to bring the amdgpu code in line with the current radeon code. > With this patch, the amdgpu driver works fine for me on my 32 bit > kernel: All graphics output looks the way it's supposed to, even with > full acceleration enabled - great! > > I'd suggest that it might be a good idea to put to apply the above > patch or something similar to the official sources. Indeed. Do you want to create a proper patch and submit it to the amd-gfx mailing list for review? See Documentation/SubmittingPatches for more information. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer
