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.
v2: Rebase
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_gem_request.c | 13 +++++++++----
drivers/gpu/drm/i915/i915_gpu_error.c | 6 ++++--
3 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 309000af003d..aacce6625f84 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -557,6 +557,7 @@ struct drm_i915_error_state {
struct drm_i915_error_request {
long jiffies;
u32 seqno;
+ u32 head;
u32 tail;
} *requests;
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 389a26429744..f50f25a27bd0 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -393,6 +393,13 @@ 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:
@@ -469,8 +476,6 @@ void __i915_add_request(struct drm_i915_gem_request *request,
trace_i915_gem_request_add(request);
- request->head = request_start;
-
/* Whilst this request exists, batch_obj will be on the
* active_list, and so will hold the active reference. Only when this
* request is retired will the the batch_obj be moved onto the
@@ -490,10 +495,10 @@ void __i915_add_request(struct drm_i915_gem_request *request,
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;
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index cc28ad429dd8..b150147fc25b 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -455,9 +455,10 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
dev_priv->engine[i].name,
ee->num_requests);
for (j = 0; j < ee->num_requests; j++) {
- err_printf(m, " seqno 0x%08x, emitted %ld, tail 0x%08x\n",
+ err_printf(m, " seqno 0x%08x, emitted %ld, head 0x%08x tail 0x%08x\n",
ee->requests[j].seqno,
ee->requests[j].jiffies,
+ ee->requests[j].head,
ee->requests[j].tail);
}
}
@@ -1205,7 +1206,8 @@ static void i915_gem_record_rings(struct drm_i915_private *dev_priv,
erq = &ee->requests[count++];
erq->seqno = request->fence.seqno;
erq->jiffies = request->emitted_jiffies;
- erq->tail = request->postfix;
+ erq->head = request->head;
+ erq->tail = request->tail;
}
}
}
--
2.8.1
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