From a21ef715fbb8210c50b1d684145f8acdf2339596 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 15 Jun 2017 14:11:29 +0100 Subject: drm/i915: Differentiate between sw write location into ring and last hw read We need to keep track of the last location we ask the hw to read up to (RING_TAIL) separately from our last write location into the ring, so that in the event of a GPU reset we do not tell the HW to proceed into a partially written request (which can happen if that request is waiting for an external signal before being executed). v2: Refactor intel_ring_reset() (Mika) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100144 Testcase: igt/gem_exec_fence/await-hang Fixes: 821ed7df6e2a ("drm/i915: Update reset path to fix incomplete requests") Fixes: d55ac5bf97c6 ("drm/i915: Defer transfer onto execution timeline to actual hw submission") Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Mika Kuoppala Link: http://patchwork.freedesktop.org/patch/msgid/20170425130049.26147-1-chris@chris-wilson.co.uk Reviewed-by: Mika Kuoppala (cherry picked from commit e6ba9992de6c63fe86c028b4876338e1cb7dac34) Signed-off-by: Jani Nikula Link: http://patchwork.freedesktop.org/patch/msgid/20170615131129.3061-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_ringbuffer.c | 41 ++++++++++++++++++++++----------- 1 file changed, 27 insertions(+), 14 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_ringbuffer.c') diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index 66a2b8b83972..513a0f4b469b 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -49,7 +49,7 @@ static int __intel_ring_space(int head, int tail, int size) void intel_ring_update_space(struct intel_ring *ring) { - ring->space = __intel_ring_space(ring->head, ring->tail, ring->size); + ring->space = __intel_ring_space(ring->head, ring->emit, ring->size); } static int @@ -774,8 +774,8 @@ static void i9xx_submit_request(struct drm_i915_gem_request *request) i915_gem_request_submit(request); - assert_ring_tail_valid(request->ring, request->tail); - I915_WRITE_TAIL(request->engine, request->tail); + I915_WRITE_TAIL(request->engine, + intel_ring_set_tail(request->ring, request->tail)); } static void i9xx_emit_breadcrumb(struct drm_i915_gem_request *req, u32 *cs) @@ -1316,11 +1316,23 @@ err: return PTR_ERR(addr); } +void intel_ring_reset(struct intel_ring *ring, u32 tail) +{ + GEM_BUG_ON(!list_empty(&ring->request_list)); + ring->tail = tail; + ring->head = tail; + ring->emit = tail; + intel_ring_update_space(ring); +} + void intel_ring_unpin(struct intel_ring *ring) { GEM_BUG_ON(!ring->vma); GEM_BUG_ON(!ring->vaddr); + /* Discard any unused bytes beyond that submitted to hw. */ + intel_ring_reset(ring, ring->tail); + if (i915_vma_is_map_and_fenceable(ring->vma)) i915_vma_unpin_iomap(ring->vma); else @@ -1562,8 +1574,9 @@ void intel_legacy_submission_resume(struct drm_i915_private *dev_priv) struct intel_engine_cs *engine; enum intel_engine_id id; + /* Restart from the beginning of the rings for convenience */ for_each_engine(engine, dev_priv, id) - engine->buffer->head = engine->buffer->tail; + intel_ring_reset(engine->buffer, 0); } static int ring_request_alloc(struct drm_i915_gem_request *request) @@ -1616,7 +1629,7 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes) unsigned space; /* Would completion of this request free enough space? */ - space = __intel_ring_space(target->postfix, ring->tail, + space = __intel_ring_space(target->postfix, ring->emit, ring->size); if (space >= bytes) break; @@ -1641,8 +1654,8 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes) u32 *intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords) { struct intel_ring *ring = req->ring; - int remain_actual = ring->size - ring->tail; - int remain_usable = ring->effective_size - ring->tail; + int remain_actual = ring->size - ring->emit; + int remain_usable = ring->effective_size - ring->emit; int bytes = num_dwords * sizeof(u32); int total_bytes, wait_bytes; bool need_wrap = false; @@ -1678,17 +1691,17 @@ u32 *intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords) if (unlikely(need_wrap)) { GEM_BUG_ON(remain_actual > ring->space); - GEM_BUG_ON(ring->tail + remain_actual > ring->size); + GEM_BUG_ON(ring->emit + remain_actual > ring->size); /* Fill the tail with MI_NOOP */ - memset(ring->vaddr + ring->tail, 0, remain_actual); - ring->tail = 0; + memset(ring->vaddr + ring->emit, 0, remain_actual); + ring->emit = 0; ring->space -= remain_actual; } - GEM_BUG_ON(ring->tail > ring->size - bytes); - cs = ring->vaddr + ring->tail; - ring->tail += bytes; + GEM_BUG_ON(ring->emit > ring->size - bytes); + cs = ring->vaddr + ring->emit; + ring->emit += bytes; ring->space -= bytes; GEM_BUG_ON(ring->space < 0); @@ -1699,7 +1712,7 @@ u32 *intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords) int intel_ring_cacheline_align(struct drm_i915_gem_request *req) { int num_dwords = - (req->ring->tail & (CACHELINE_BYTES - 1)) / sizeof(uint32_t); + (req->ring->emit & (CACHELINE_BYTES - 1)) / sizeof(uint32_t); u32 *cs; if (num_dwords == 0) -- cgit