)]}'
{
  "commit": "e02f5c1bb2283cfcee68f2f0feddcc06150f13aa",
  "tree": "85462e83a8dd5a57914cde7aa54ba35c6d6cdbcd",
  "parents": [
    "6198f40b47f3688bcb0b2041e9fa89473d5abe3f"
  ],
  "author": {
    "name": "Ard Biesheuvel",
    "email": "ard.biesheuvel@linaro.org",
    "time": "Thu Jan 24 13:06:58 2019 +0100"
  },
  "committer": {
    "name": "Christian König",
    "email": "christian.koenig@amd.com",
    "time": "Wed Feb 06 19:32:30 2019 +0100"
  },
  "message": "drm: disable uncached DMA optimization for ARM and arm64\n\nThe DRM driver stack is designed to work with cache coherent devices\nonly, but permits an optimization to be enabled in some cases, where\nfor some buffers, both the CPU and the GPU use uncached mappings,\nremoving the need for DMA snooping and allocation in the CPU caches.\n\nThe use of uncached GPU mappings relies on the correct implementation\nof the PCIe NoSnoop TLP attribute by the platform, otherwise the GPU\nwill use cached mappings nonetheless. On x86 platforms, this does not\nseem to matter, as uncached CPU mappings will snoop the caches in any\ncase. However, on ARM and arm64, enabling this optimization on a\nplatform where NoSnoop is ignored results in loss of coherency, which\nbreaks correct operation of the device. Since we have no way of\ndetecting whether NoSnoop works or not, just disable this\noptimization entirely for ARM and arm64.\n\nCc: Christian Koenig \u003cchristian.koenig@amd.com\u003e\nCc: Alex Deucher \u003calexander.deucher@amd.com\u003e\nCc: David Zhou \u003cDavid1.Zhou@amd.com\u003e\nCc: Huang Rui \u003cray.huang@amd.com\u003e\nCc: Junwei Zhang \u003cJerry.Zhang@amd.com\u003e\nCc: Michel Daenzer \u003cmichel.daenzer@amd.com\u003e\nCc: David Airlie \u003cairlied@linux.ie\u003e\nCc: Daniel Vetter \u003cdaniel@ffwll.ch\u003e\nCc: Maarten Lankhorst \u003cmaarten.lankhorst@linux.intel.com\u003e\nCc: Maxime Ripard \u003cmaxime.ripard@bootlin.com\u003e\nCc: Sean Paul \u003csean@poorly.run\u003e\nCc: Michael Ellerman \u003cmpe@ellerman.id.au\u003e\nCc: Benjamin Herrenschmidt \u003cbenh@kernel.crashing.org\u003e\nCc: Will Deacon \u003cwill.deacon@arm.com\u003e\nCc: Christoph Hellwig \u003chch@infradead.org\u003e\nCc: Robin Murphy \u003crobin.murphy@arm.com\u003e\nCc: amd-gfx list \u003camd-gfx@lists.freedesktop.org\u003e\nCc: dri-devel \u003cdri-devel@lists.freedesktop.org\u003e\nReported-by: Carsten Haitzler \u003cCarsten.Haitzler@arm.com\u003e\nSigned-off-by: Ard Biesheuvel \u003card.biesheuvel@linaro.org\u003e\nReviewed-by: Christian König \u003cchristian.koenig@amd.com\u003e\nReviewed-by: Alex Deucher \u003calexander.deucher@amd.com\u003e\nLink: https://patchwork.kernel.org/patch/10778815/\nSigned-off-by: Christian König \u003cchristian.koenig@amd.com\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "bfe1639df02da3a705a0c9c588336b0068713d7f",
      "old_mode": 33188,
      "old_path": "include/drm/drm_cache.h",
      "new_id": "97fc498dc7672b4274147955c21a6807082fbaa5",
      "new_mode": 33188,
      "new_path": "include/drm/drm_cache.h"
    }
  ]
}