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Chris Wilson authored
If the request->wa_tail is 0 (because it landed exactly on the end of the ringbuffer), when we reconstruct request->tail following a reset we fill in an illegal value (-8 or 0x001ffff8). As a result, RING_HEAD is never able to catch up with RING_TAIL and the GPU spins endlessly. If the ring contains a couple of breadcrumbs, even our hangcheck is unable to catch the busy-looping as the ACTHD and seqno continually advance. v2: Move the wrap into a common intel_ring_wrap(). Fixes: a3aabe86 ("drm/i915/execlists: Reinitialise context image after GPU hang") Signed-off-by:
Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@intel.com> Cc: <stable@vger.kernel.org> # v4.10+ Link: http://patchwork.freedesktop.org/patch/msgid/20170327130009.4678-1-chris@chris-wilson.co.ukReviewed-by:
Mika Kuoppala <mika.kuoppala@intel.com>
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