drm/i915: Remove intel_ring.last_retired_head

Storing the position of the breadcrumb of the last retired request as
a separate last_retired_head is superfluous as we always copy that into
head prior to recalculation of the intel_ring.space.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170321102552.24357-1-chris@chris-wilson.co.uk

1 files changed, 4 insertions, 17 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index d9b8d17c3fc6..0ca5ea7a9407 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -49,13 +49,7 @@ static int __intel_ring_space(int head, int tail, int size)
 
 void intel_ring_update_space(struct intel_ring *ring)
 {
-        if (ring->last_retired_head != -1) {
-                ring->head = ring->last_retired_head;
-                ring->last_retired_head = -1;
-        }
-
-        ring->space = __intel_ring_space(ring->head & HEAD_ADDR,
-                                         ring->tail, ring->size);
+        ring->space = __intel_ring_space(ring->head, ring->tail, ring->size);
 }
 
 static int
@@ -618,12 +612,8 @@ static void reset_ring_common(struct intel_engine_cs *engine,
                 }
 
                 /* If the rq hung, jump to its breadcrumb and skip the batch */
-                if (request->fence.error == -EIO) {
-                        struct intel_ring *ring = request->ring;
-
-                        ring->head = request->postfix;
-                        ring->last_retired_head = -1;
-                }
+                if (request->fence.error == -EIO)
+                        request->ring->head = request->postfix;
         } else {
                 engine->legacy_active_context = NULL;
         }
@@ -1392,7 +1382,6 @@ intel_engine_create_ring(struct intel_engine_cs *engine, int size)
         if (IS_I830(engine->i915) || IS_I845G(engine->i915))
                 ring->effective_size -= 2 * CACHELINE_BYTES;
 
-        ring->last_retired_head = -1;
         intel_ring_update_space(ring);
 
         vma = intel_ring_create_vma(engine->i915, size);
@@ -1571,10 +1560,8 @@ void intel_legacy_submission_resume(struct drm_i915_private *dev_priv)
         struct intel_engine_cs *engine;
         enum intel_engine_id id;
 
-        for_each_engine(engine, dev_priv, id) {
+        for_each_engine(engine, dev_priv, id)
                 engine->buffer->head = engine->buffer->tail;
-                engine->buffer->last_retired_head = -1;
-        }
 }
 
 static int ring_request_alloc(struct drm_i915_gem_request *request)