tree 5e0a2ee7d9248f00909764bc734e15715df1375c
parent 3d5564e91025bd17d93d0a23ebf8e22309652591
author Chris Wilson <chris@chris-wilson.co.uk> 1467390204 +0100
committer Chris Wilson <chris@chris-wilson.co.uk> 1467403255 +0100

drm/i915: Stop setting wraparound seqno on initialisation

We have testcases to ensure that seqno wraparound works fine, so we can
forgo forcing everyone to encounter seqno wraparound during early
uptime. seqno wraparound incurs a full GPU stall so not forcing it
will eliminate one jitter from the early system. Using the testcases, we
have very deterministic testing which given how difficult it would be to
debug an issue (GPU hang) stemming from a wraparound using pure
postmortem analysis I see no value in forcing a wrap during boot.

Advancing the global next_seqno after a GPU reset is equally pointless.

References? https://bugs.freedesktop.org/show_bug.cgi?id=95023
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1467390209-3576-15-git-send-email-chris@chris-wilson.co.uk