drm/i915: Ensure OLS & PLR are always in sync
The aim is to replace seqno values with request structures. A step along the way
is to switch to using the PLR in preference to the OLS. That requires the PLR to
only be valid when and only when the OLS is also valid. I.e., the two must be
kept in lock step. Then, code which was using the OLS can be safely switched
over to using the PLR instead.
For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 1d01b51..9fe1307 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -2024,20 +2024,33 @@
static int
intel_ring_alloc_seqno(struct intel_engine_cs *ring)
{
- if (ring->outstanding_lazy_seqno)
+ int ret;
+ struct drm_i915_gem_request *request;
+
+ /* XXX: The aim is to replace seqno values with request structures.
+ * A step along the way is to switch to using the PLR in preference
+ * to the OLS. That requires the PLR to only be valid when the OLS
+ * is also valid. I.e., the two must be kept in step. */
+
+ if (ring->outstanding_lazy_seqno) {
+ WARN_ON(ring->preallocated_lazy_request == NULL);
return 0;
-
- if (ring->preallocated_lazy_request == NULL) {
- struct drm_i915_gem_request *request;
-
- request = kmalloc(sizeof(*request), GFP_KERNEL);
- if (request == NULL)
- return -ENOMEM;
-
- ring->preallocated_lazy_request = request;
}
- return i915_gem_get_seqno(ring->dev, &ring->outstanding_lazy_seqno);
+ WARN_ON(ring->preallocated_lazy_request != NULL);
+
+ request = kmalloc(sizeof(*request), GFP_KERNEL);
+ if (request == NULL)
+ return -ENOMEM;
+
+ ret = i915_gem_get_seqno(ring->dev, &ring->outstanding_lazy_seqno);
+ if (ret) {
+ kfree(request);
+ return ret;
+ }
+
+ ring->preallocated_lazy_request = request;
+ return 0;
}
static int __intel_ring_prepare(struct intel_engine_cs *ring,