On 2018-12-23 10:44 p.m., Yu Zhao wrote: > On Fri, Dec 21, 2018 at 10:07:26AM +0100, Michel Dänzer wrote: >> On 2018-12-21 4:10 a.m., Yu Zhao wrote: >>> Userspace may request pitch alignment that is not supported by GPU. >>> Some requests 32, but GPU ignores it and uses default 64 when cpp is >>> 4. If GEM object is allocated based on the smaller alignment, GPU >>> DMA will go out of bound. >>> >>> For GPU that does frame buffer compression, DMA writing out of bound >>> memory will cause memory corruption. >>> >>> Signed-off-by: Yu Zhao <yuz...@google.com> >>> --- >>> drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 9 +++++++++ >>> 1 file changed, 9 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c >>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c >>> index e309d26170db..755daa332f8a 100644 >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c >>> @@ -527,6 +527,15 @@ amdgpu_display_user_framebuffer_create(struct >>> drm_device *dev, >>> struct drm_gem_object *obj; >>> struct amdgpu_framebuffer *amdgpu_fb; >>> int ret; >>> + struct amdgpu_device *adev = dev->dev_private; >>> + int cpp = drm_format_plane_cpp(mode_cmd->pixel_format, 0); >>> + int pitch = amdgpu_align_pitch(adev, mode_cmd->width, cpp, false); >> >> Also, this needs to use mode_cmd->pitches instead of mode_cmd->width, >> otherwise it'll spuriously fail for larger but well-aligned pitches. > > Actually mode_cmd->pitches is aligned mode_cmd->width multiplied > by cpp. So we can't just use mode_cmd->pitches.
Use mode_cmd->pitches / cpp then? > And I'm not sure if the hardware works with larger alignment It does. > (it certainly ignores smaller alignment). Yeah, pitch must be >= width. Maybe this patch could check that as well. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ amd-gfx mailing list firstname.lastname@example.org https://lists.freedesktop.org/mailman/listinfo/amd-gfx