From 450362d3fe866b14304f309b5fffba0c33fbfbc3 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 27 Mar 2017 14:00:07 +0100 Subject: drm/i915/execlists: Wrap tail pointer after reset tweaking 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: a3aabe86a340 ("drm/i915/execlists: Reinitialise context image after GPU hang") Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: # v4.10+ Link: http://patchwork.freedesktop.org/patch/msgid/20170327130009.4678-1-chris@chris-wilson.co.uk Reviewed-by: Mika Kuoppala --- drivers/gpu/drm/i915/intel_ringbuffer.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_ringbuffer.h') diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index 166aa1ae65cf..17ac44980d84 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -515,12 +515,18 @@ intel_ring_advance(struct drm_i915_gem_request *req, u32 *cs) } static inline u32 -intel_ring_offset(struct drm_i915_gem_request *req, void *addr) +intel_ring_wrap(const struct intel_ring *ring, u32 pos) +{ + return pos & (ring->size - 1); +} + +static inline u32 +intel_ring_offset(const struct drm_i915_gem_request *req, void *addr) { /* Don't write ring->size (equivalent to 0) as that hangs some GPUs. */ u32 offset = addr - req->ring->vaddr; GEM_BUG_ON(offset > req->ring->size); - return offset & (req->ring->size - 1); + return intel_ring_wrap(req->ring, offset); } void intel_ring_update_space(struct intel_ring *ring); -- cgit v1.2.3