drm/i915: Allow sharing the idle-barrier from other kernel requests
By placing our idle-barriers in the i915_active fence tree, we expose those for reuse by other components that are issuing requests along the kernel_context. Reusing the proto-barrier active_node is perfectly fine as the new request implies a context-switch, and so an opportune point to run the idle-barrier. However, the proto-barrier is not equivalent to a normal active_node and care must be taken to avoid dereferencing the ERR_PTR used as its request marker. v2: Comment the more egregious cheek v3: A glossary! Reported-by:Lionel Landwerlin <lionel.g.landwerlin@intel.com> Fixes: ce476c80 ("drm/i915: Keep contexts pinned until after the next kernel context switch") Fixes: a9877da2 ("drm/i915/oa: Reconfigure contexts on the fly") Signed-off-by:
Chris Wilson <chris@chris-wilson.co.uk> Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by:
Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190802100015.1281-1-chris@chris-wilson.co.uk
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