On 8/15/2016 9:18 PM, Tvrtko Ursulin wrote:

On 15/08/16 15:49, akash.g...@intel.com wrote:
From: Sagar Arun Kamble <sagar.a.kam...@intel.com>

Before capturing the GuC logs as a part of error state, there should be a
force log buffer flush action sent to GuC before proceeding with GPU
reset
and re-initializing GUC. There could be some data in the log buffer which
is yet to be captured and those logs would be particularly useful to
understand that why the GPU reset was initiated.

v2:
- Avoid the wait via flush_work, to serialize against an ongoing log
   buffer flush, from the error state capture path. (Chris)

Could you explain if the patch does anything now that the flush has been
removed?

flush_work for the regular log buffer flush work item has been removed
but the forceful command is still sent to GuC.

In fact I don't even understand what it was doing before. :)

I am sorry for that.

If the idea is to send a flush command to GuC so it can raise an
interrupt for a partially full buffer,
Yes exactly this is the idea.

then i915_guc_flush_logs should
send the flush command and wait for that interrupt/work.

But the function is first waiting for the work item to complete and then
sending the flush command to the GuC. So I am confused.

Actually GuC firmware just ignores the forceful flush command received from Host, if it sees there is a pending request for regular log buffer
flush, for which it hasn't received the ack.

So that's why from Host side, before sending the forceful flush command to GuC, had to first wait for the regular log buffer flush work item to
finish execution.

Best regards
Akash

Regards,

Tvrtko

- Rebase.

Signed-off-by: Sagar Arun Kamble <sagar.a.kam...@intel.com>
Signed-off-by: Akash Goel <akash.g...@intel.com>
---
  drivers/gpu/drm/i915/i915_gpu_error.c      |  2 ++
  drivers/gpu/drm/i915/i915_guc_submission.c | 30
++++++++++++++++++++++++++++++
  drivers/gpu/drm/i915/intel_guc.h           |  1 +
  3 files changed, 33 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c
b/drivers/gpu/drm/i915/i915_gpu_error.c
index 94297aa..b73c671 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1301,6 +1301,8 @@ static void
i915_gem_capture_guc_log_buffer(struct drm_i915_private *dev_priv,
      if (!dev_priv->guc.log.vma || (i915.guc_log_level < 0))
          return;

+    i915_guc_flush_logs(dev_priv, false);
+
      error->guc_log = i915_error_object_create(dev_priv,
                            dev_priv->guc.log.vma);
  }
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c
b/drivers/gpu/drm/i915/i915_guc_submission.c
index b8d6313..85df2f3 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -185,6 +185,16 @@ static int
host2guc_logbuffer_flush_complete(struct intel_guc *guc)
      return host2guc_action(guc, data, 1);
  }

+static int host2guc_force_logbuffer_flush(struct intel_guc *guc)
+{
+    u32 data[2];
+
+    data[0] = HOST2GUC_ACTION_FORCE_LOG_BUFFER_FLUSH;
+    data[1] = 0;
+
+    return host2guc_action(guc, data, 2);
+}
+
  /*
   * Initialise, update, or clear doorbell data shared with the GuC
   *
@@ -1536,6 +1546,26 @@ void i915_guc_capture_logs(struct
drm_i915_private *dev_priv)
      intel_runtime_pm_put(dev_priv);
  }

+void i915_guc_flush_logs(struct drm_i915_private *dev_priv, bool
can_wait)
+{
+    if (!i915.enable_guc_submission || (i915.guc_log_level < 0))
+        return;
+
+    /* First disable the interrupts, will be renabled afterwards */
+    gen9_disable_guc_interrupts(dev_priv);
+
+    /* Before initiating the forceful flush, wait for any
pending/ongoing
+     * flush to complete otherwise forceful flush may not happen, but
wait
+     * can't be done for some paths like error state capture in which
case
+     * take a chance & directly attempt the forceful flush.
+     */
+    if (can_wait)
+        flush_work(&dev_priv->guc.log.flush_work);
+
+    /* Ask GuC to update the log buffer state */
+    host2guc_force_logbuffer_flush(&dev_priv->guc);
+}
+
  void i915_guc_unregister(struct drm_i915_private *dev_priv)
  {
      if (!i915.enable_guc_submission)
diff --git a/drivers/gpu/drm/i915/intel_guc.h
b/drivers/gpu/drm/i915/intel_guc.h
index 8598f38..d7eda42 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -182,6 +182,7 @@ int i915_guc_wq_check_space(struct
drm_i915_gem_request *rq);
  void i915_guc_submission_disable(struct drm_i915_private *dev_priv);
  void i915_guc_submission_fini(struct drm_i915_private *dev_priv);
  void i915_guc_capture_logs(struct drm_i915_private *dev_priv);
+void i915_guc_flush_logs(struct drm_i915_private *dev_priv, bool
can_wait);
  void i915_guc_register(struct drm_i915_private *dev_priv);
  void i915_guc_unregister(struct drm_i915_private *dev_priv);


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