diff mbox series

[v1,3/3] drm/i915/gt: Timeout when waiting for idle in suspending

Message ID 20230802233501.17074-4-alan.previn.teres.alexis@intel.com (mailing list archive)
State New, archived
Headers show
Series Resolve suspend-resume racing with GuC destroy-context-worker | expand

Commit Message

Teres Alexis, Alan Previn Aug. 2, 2023, 11:35 p.m. UTC 
When suspending, add a timeout when calling
intel_gt_pm_wait_for_idle else if we have a lost
G2H event that holds a wakeref (which would be
indicating of a bug elsewhere in the driver), we
get to complete the suspend-resume cycle, albeit
without all the lower power hw counters hitting
its targets, instead of hanging in the kernel.

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
---
 drivers/gpu/drm/i915/gt/intel_engine_cs.c |  2 +-
 drivers/gpu/drm/i915/gt/intel_gt_pm.c     |  7 ++++++-
 drivers/gpu/drm/i915/gt/intel_gt_pm.h     |  7 ++++++-
 drivers/gpu/drm/i915/intel_wakeref.c      | 14 ++++++++++----
 drivers/gpu/drm/i915/intel_wakeref.h      |  5 +++--
 5 files changed, 26 insertions(+), 9 deletions(-)

Comments

Rodrigo Vivi Aug. 7, 2023, 5:56 p.m. UTC | #1 
On Wed, Aug 02, 2023 at 04:35:01PM -0700, Alan Previn wrote:
> When suspending, add a timeout when calling
> intel_gt_pm_wait_for_idle else if we have a lost
> G2H event that holds a wakeref (which would be
> indicating of a bug elsewhere in the driver), we
> get to complete the suspend-resume cycle, albeit
> without all the lower power hw counters hitting
> its targets, instead of hanging in the kernel.
> 
> Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_engine_cs.c |  2 +-
>  drivers/gpu/drm/i915/gt/intel_gt_pm.c     |  7 ++++++-
>  drivers/gpu/drm/i915/gt/intel_gt_pm.h     |  7 ++++++-
>  drivers/gpu/drm/i915/intel_wakeref.c      | 14 ++++++++++----
>  drivers/gpu/drm/i915/intel_wakeref.h      |  5 +++--
>  5 files changed, 26 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> index ee15486fed0d..090438eb8682 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> @@ -688,7 +688,7 @@ void intel_engines_release(struct intel_gt *gt)
>  		if (!engine->release)
>  			continue;
>  
> -		intel_wakeref_wait_for_idle(&engine->wakeref);
> +		intel_wakeref_wait_for_idle(&engine->wakeref, 0);
>  		GEM_BUG_ON(intel_engine_pm_is_awake(engine));
>  
>  		engine->release(engine);
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> index 3162d859ed68..dfe77eb3efd1 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> @@ -289,6 +289,8 @@ int intel_gt_resume(struct intel_gt *gt)
>  
>  static void wait_for_suspend(struct intel_gt *gt)
>  {
> +	int timeout_ms = CONFIG_DRM_I915_MAX_REQUEST_BUSYWAIT ? : 10000;
> +
>  	if (!intel_gt_pm_is_awake(gt)) {
>  		intel_uc_suspend_prepare(&gt->uc);
>  		return;
> @@ -305,7 +307,10 @@ static void wait_for_suspend(struct intel_gt *gt)
>  		intel_uc_suspend_prepare(&gt->uc);
>  	}
>  
> -	intel_gt_pm_wait_for_idle(gt);
> +	/* we are suspending, so we shouldn't be waiting forever */
> +	if (intel_gt_pm_wait_timeout_for_idle(gt, timeout_ms) == -ETIME)
> +		drm_warn(&gt->i915->drm, "Bailing from %s after %d milisec timeout\n",
> +			 __func__, timeout_ms);
>  }
>  
>  void intel_gt_suspend_prepare(struct intel_gt *gt)
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> index 6c9a46452364..5358acc2b5b1 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> @@ -68,7 +68,12 @@ static inline void intel_gt_pm_might_put(struct intel_gt *gt)
>  
>  static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt)
>  {
> -	return intel_wakeref_wait_for_idle(&gt->wakeref);
> +	return intel_wakeref_wait_for_idle(&gt->wakeref, 0);
> +}
> +
> +static inline int intel_gt_pm_wait_timeout_for_idle(struct intel_gt *gt, int timeout_ms)
> +{
> +	return intel_wakeref_wait_for_idle(&gt->wakeref, timeout_ms);
>  }
>  
>  void intel_gt_pm_init_early(struct intel_gt *gt);
> diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
> index 718f2f1b6174..7e01d4cc300c 100644
> --- a/drivers/gpu/drm/i915/intel_wakeref.c
> +++ b/drivers/gpu/drm/i915/intel_wakeref.c
> @@ -111,14 +111,20 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
>  			 "wakeref.work", &key->work, 0);
>  }
>  
> -int intel_wakeref_wait_for_idle(struct intel_wakeref *wf)
> +int intel_wakeref_wait_for_idle(struct intel_wakeref *wf, int timeout_ms)
>  {
> -	int err;
> +	int err = 0;
>  
>  	might_sleep();
>  
> -	err = wait_var_event_killable(&wf->wakeref,
> -				      !intel_wakeref_is_active(wf));
> +	if (!timeout_ms)
> +		err = wait_var_event_killable(&wf->wakeref,
> +					      !intel_wakeref_is_active(wf));
> +	else if (wait_var_event_timeout(&wf->wakeref,
> +					!intel_wakeref_is_active(wf),
> +					msecs_to_jiffies(timeout_ms)) < 1)
> +		err = -ETIME;

it looks to me that -ETIMEDOUT would be a better error.

> +
>  	if (err)
>  		return err;
>  
> diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h
> index ec881b097368..6fbb7a2fb6ea 100644
> --- a/drivers/gpu/drm/i915/intel_wakeref.h
> +++ b/drivers/gpu/drm/i915/intel_wakeref.h
> @@ -251,15 +251,16 @@ __intel_wakeref_defer_park(struct intel_wakeref *wf)
>  /**
>   * intel_wakeref_wait_for_idle: Wait until the wakeref is idle
>   * @wf: the wakeref
> + * @timeout_ms: timeout to wait in milisecs, zero means forever
>   *
>   * Wait for the earlier asynchronous release of the wakeref. Note
>   * this will wait for any third party as well, so make sure you only wait
>   * when you have control over the wakeref and trust no one else is acquiring
>   * it.
>   *
> - * Return: 0 on success, error code if killed.
> + * Return: 0 on success, error code if killed, -ETIME if timed-out.
>   */
> -int intel_wakeref_wait_for_idle(struct intel_wakeref *wf);
> +int intel_wakeref_wait_for_idle(struct intel_wakeref *wf, int timeout_ms);
>  
>  struct intel_wakeref_auto {
>  	struct drm_i915_private *i915;
> -- 
> 2.39.0
>
Teres Alexis, Alan Previn Aug. 9, 2023, 7:38 p.m. UTC | #2 
Thanks Rodrigo for reviewing this.

On Mon, 2023-08-07 at 13:56 -0400, Vivi, Rodrigo wrote:
> On Wed, Aug 02, 2023 at 04:35:01PM -0700, Alan Previn wrote:
> > When suspending, add a timeout when calling
> > intel_gt_pm_wait_for_idle else if we have a lost
> > G2H event that holds a wakeref (which would be
> > indicating of a bug elsewhere in the driver), we
> > get to complete the suspend-resume cycle, albeit
> > without all the lower power hw counters hitting
> > its targets, instead of hanging in the kernel.
> > 
alan:snip

> > -int intel_wakeref_wait_for_idle(struct intel_wakeref *wf)
> > +int intel_wakeref_wait_for_idle(struct intel_wakeref *wf, int timeout_ms)
> >  {
> > -	int err;
> > +	int err = 0;
> >  
> >  	might_sleep();
> >  
> > -	err = wait_var_event_killable(&wf->wakeref,
> > -				      !intel_wakeref_is_active(wf));
> > +	if (!timeout_ms)
> > +		err = wait_var_event_killable(&wf->wakeref,
> > +					      !intel_wakeref_is_active(wf));
> > +	else if (wait_var_event_timeout(&wf->wakeref,
> > +					!intel_wakeref_is_active(wf),
> > +					msecs_to_jiffies(timeout_ms)) < 1)
> > +		err = -ETIME;
> 
> it looks to me that -ETIMEDOUT would be a better error.
alan: okay - will do, thanks.
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index ee15486fed0d..090438eb8682 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -688,7 +688,7 @@  void intel_engines_release(struct intel_gt *gt)
 		if (!engine->release)
 			continue;
 
-		intel_wakeref_wait_for_idle(&engine->wakeref);
+		intel_wakeref_wait_for_idle(&engine->wakeref, 0);
 		GEM_BUG_ON(intel_engine_pm_is_awake(engine));
 
 		engine->release(engine);
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index 3162d859ed68..dfe77eb3efd1 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -289,6 +289,8 @@  int intel_gt_resume(struct intel_gt *gt)
 
 static void wait_for_suspend(struct intel_gt *gt)
 {
+	int timeout_ms = CONFIG_DRM_I915_MAX_REQUEST_BUSYWAIT ? : 10000;
+
 	if (!intel_gt_pm_is_awake(gt)) {
 		intel_uc_suspend_prepare(&gt->uc);
 		return;
@@ -305,7 +307,10 @@  static void wait_for_suspend(struct intel_gt *gt)
 		intel_uc_suspend_prepare(&gt->uc);
 	}
 
-	intel_gt_pm_wait_for_idle(gt);
+	/* we are suspending, so we shouldn't be waiting forever */
+	if (intel_gt_pm_wait_timeout_for_idle(gt, timeout_ms) == -ETIME)
+		drm_warn(&gt->i915->drm, "Bailing from %s after %d milisec timeout\n",
+			 __func__, timeout_ms);
 }
 
 void intel_gt_suspend_prepare(struct intel_gt *gt)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
index 6c9a46452364..5358acc2b5b1 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
@@ -68,7 +68,12 @@  static inline void intel_gt_pm_might_put(struct intel_gt *gt)
 
 static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt)
 {
-	return intel_wakeref_wait_for_idle(&gt->wakeref);
+	return intel_wakeref_wait_for_idle(&gt->wakeref, 0);
+}
+
+static inline int intel_gt_pm_wait_timeout_for_idle(struct intel_gt *gt, int timeout_ms)
+{
+	return intel_wakeref_wait_for_idle(&gt->wakeref, timeout_ms);
 }
 
 void intel_gt_pm_init_early(struct intel_gt *gt);
diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
index 718f2f1b6174..7e01d4cc300c 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.c
+++ b/drivers/gpu/drm/i915/intel_wakeref.c
@@ -111,14 +111,20 @@  void __intel_wakeref_init(struct intel_wakeref *wf,
 			 "wakeref.work", &key->work, 0);
 }
 
-int intel_wakeref_wait_for_idle(struct intel_wakeref *wf)
+int intel_wakeref_wait_for_idle(struct intel_wakeref *wf, int timeout_ms)
 {
-	int err;
+	int err = 0;
 
 	might_sleep();
 
-	err = wait_var_event_killable(&wf->wakeref,
-				      !intel_wakeref_is_active(wf));
+	if (!timeout_ms)
+		err = wait_var_event_killable(&wf->wakeref,
+					      !intel_wakeref_is_active(wf));
+	else if (wait_var_event_timeout(&wf->wakeref,
+					!intel_wakeref_is_active(wf),
+					msecs_to_jiffies(timeout_ms)) < 1)
+		err = -ETIME;
+
 	if (err)
 		return err;
 
diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h
index ec881b097368..6fbb7a2fb6ea 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.h
+++ b/drivers/gpu/drm/i915/intel_wakeref.h
@@ -251,15 +251,16 @@  __intel_wakeref_defer_park(struct intel_wakeref *wf)
 /**
  * intel_wakeref_wait_for_idle: Wait until the wakeref is idle
  * @wf: the wakeref
+ * @timeout_ms: timeout to wait in milisecs, zero means forever
  *
  * Wait for the earlier asynchronous release of the wakeref. Note
  * this will wait for any third party as well, so make sure you only wait
  * when you have control over the wakeref and trust no one else is acquiring
  * it.
  *
- * Return: 0 on success, error code if killed.
+ * Return: 0 on success, error code if killed, -ETIME if timed-out.
  */
-int intel_wakeref_wait_for_idle(struct intel_wakeref *wf);
+int intel_wakeref_wait_for_idle(struct intel_wakeref *wf, int timeout_ms);
 
 struct intel_wakeref_auto {
 	struct drm_i915_private *i915;