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authorChris Wilson <chris@chris-wilson.co.uk>2016-08-15 10:48:40 +0100
committerChris Wilson <chris@chris-wilson.co.uk>2016-08-15 11:00:49 +0100
commitd045446df196e3af341aa7623de5d21049ec4f67 (patch)
treedcbf52e6ed0bb044c267b082ad94f6ca62041ac6 /drivers/gpu/drm/i915/i915_gem_request.c
parent7466c291b1d2fa38e3140717c857c86e0eac1b6b (diff)
drm/i915: Record the position of the start of the request
Not only does it make for good documentation and debugging aide, but it is also vital for when we want to unwind requests - such as when throwing away an incomplete request. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/1470414607-32453-2-git-send-email-arun.siluvery@linux.intel.com Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1471254551-25805-1-git-send-email-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gem_request.c')
-rw-r--r--drivers/gpu/drm/i915/i915_gem_request.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index b764c1d440c86..8a9e9bfeea093 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -426,6 +426,13 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
if (ret)
goto err_ctx;
+ /* Record the position of the start of the request so that
+ * should we detect the updated seqno part-way through the
+ * GPU processing the request, we never over-estimate the
+ * position of the head.
+ */
+ req->head = req->ring->tail;
+
return req;
err_ctx:
@@ -500,8 +507,6 @@ void __i915_add_request(struct drm_i915_gem_request *request, bool flush_caches)
trace_i915_gem_request_add(request);
- request->head = request_start;
-
/* Seal the request and mark it as pending execution. Note that
* we may inspect this state, without holding any locks, during
* hangcheck. Hence we apply the barrier to ensure that we do not
@@ -514,10 +519,10 @@ void __i915_add_request(struct drm_i915_gem_request *request, bool flush_caches)
list_add_tail(&request->link, &engine->request_list);
list_add_tail(&request->ring_link, &ring->request_list);
- /* Record the position of the start of the request so that
+ /* Record the position of the start of the breadcrumb so that
* should we detect the updated seqno part-way through the
* GPU processing the request, we never over-estimate the
- * position of the head.
+ * position of the ring's HEAD.
*/
request->postfix = ring->tail;