drm/i915: Check incoming alignment for unfenced buffers (on i915gm)
In case the object has changed tiling between calls to execbuf, we need to check if the existing offset inside the GTT matches the new tiling constraint. We even need to do this for "unfenced" tiled objects, where the 3D commands use an implied fence and so the object still needs to match the physical fence restrictions on alignment (only required for gen2 and early gen3). In commit 2889caa9 ("drm/i915: Eliminate lots of iterations over the execobjects array"), the idea was to remove the second guessing and only set the NEEDS_MAP flag when required. However, the entire check for an unusable offset for fencing was removed and not just the secondary check. I.e. /* avoid costly ping-pong once a batch bo ended up non-mappable */ if (entry->flags & __EXEC_OBJECT_NEEDS_MAP && !i915_vma_is_map_and_fenceable(vma)) return !only_mappable_for_reloc(entry->flags); was entirely removed as the ping-pong between execbuf passes was fixed, but its primary purpose in forcing unaligned unfenced access to be rebound was forgotten. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103502 Fixes: 2889caa9 ("drm/i915: Eliminate lots of iterations over the execobjects array") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20171031103607.17836-1-chris@chris-wilson.co.ukReviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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