On Wed, 6 Feb 2019 at 19:38, Christian König ckoenig.leichtzumerken@gmail.com wrote:
Am 06.02.19 um 18:23 schrieb Ard Biesheuvel:
On Fri, 25 Jan 2019 at 11:35, Ard Biesheuvel ard.biesheuvel@linaro.org wrote:
On Fri, 25 Jan 2019 at 12:30, Christian König ckoenig.leichtzumerken@gmail.com wrote:
Am 25.01.19 um 09:43 schrieb Ard Biesheuvel:
On Thu, 24 Jan 2019 at 15:01, Alex Deucher alexdeucher@gmail.com wrote:
On Thu, Jan 24, 2019 at 9:00 AM Ard Biesheuvel ard.biesheuvel@linaro.org wrote: > On Thu, 24 Jan 2019 at 13:31, Koenig, Christian > Christian.Koenig@amd.com wrote: >> Am 24.01.19 um 13:06 schrieb Ard Biesheuvel: >>> The DRM driver stack is designed to work with cache coherent devices >>> only, but permits an optimization to be enabled in some cases, where >>> for some buffers, both the CPU and the GPU use uncached mappings, >>> removing the need for DMA snooping and allocation in the CPU caches. >>> >>> The use of uncached GPU mappings relies on the correct implementation >>> of the PCIe NoSnoop TLP attribute by the platform, otherwise the GPU >>> will use cached mappings nonetheless. On x86 platforms, this does not >>> seem to matter, as uncached CPU mappings will snoop the caches in any >>> case. However, on ARM and arm64, enabling this optimization on a >>> platform where NoSnoop is ignored results in loss of coherency, which >>> breaks correct operation of the device. Since we have no way of >>> detecting whether NoSnoop works or not, just disable this >>> optimization entirely for ARM and arm64. >>> >>> Cc: Christian Koenig christian.koenig@amd.com >>> Cc: Alex Deucher alexander.deucher@amd.com >>> Cc: David Zhou David1.Zhou@amd.com >>> Cc: Huang Rui ray.huang@amd.com >>> Cc: Junwei Zhang Jerry.Zhang@amd.com >>> Cc: Michel Daenzer michel.daenzer@amd.com >>> Cc: David Airlie airlied@linux.ie >>> Cc: Daniel Vetter daniel@ffwll.ch >>> Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com >>> Cc: Maxime Ripard maxime.ripard@bootlin.com >>> Cc: Sean Paul sean@poorly.run >>> Cc: Michael Ellerman mpe@ellerman.id.au >>> Cc: Benjamin Herrenschmidt benh@kernel.crashing.org >>> Cc: Will Deacon will.deacon@arm.com >>> Cc: Christoph Hellwig hch@infradead.org >>> Cc: Robin Murphy robin.murphy@arm.com >>> Cc: amd-gfx list amd-gfx@lists.freedesktop.org >>> Cc: dri-devel dri-devel@lists.freedesktop.org >>> Reported-by: Carsten Haitzler Carsten.Haitzler@arm.com >>> Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org >> The subject line should probably read "disable uncached...". >> > Ugh, of course ... > >> With that fixed the patch is Reviewed-by: Christian König >> christian.koenig@amd.com. >> Same: Reviewed-by: Alex Deucher alexander.deucher@amd.com
Thanks all
Should I resend the patch with the subject corrected?
I will update the subject line and push it upstream through drm-misc-next if nobody objects.
Wonderful, thanks.
Hi Christian,
Are you still planning to merge this for v5.1?
My bad, only pushed this to our internal branch, but forgot out drm-misc-next.
Fixed now, thanks for the reminder.
Thanks,
Does anyone mind if I propose this patch for backporting to v4.19 or earlier once it gets merged for v5.1?