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
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index bf193ba..b101795 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_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 b764c1d..8a9e9bf 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -426,6 +426,13 @@
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 @@
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 @@
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 eecb870..d54848f 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -455,9 +455,10 @@
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 @@
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;
}
}
}
