[Intel-gfx] [PATCH 12/12] drm/i915: Cache the reset_counter for the request

Daniel Vetter daniel at ffwll.ch
Tue Nov 24 08:43:22 PST 2015


On Fri, Nov 20, 2015 at 12:43:52PM +0000, Chris Wilson wrote:
> Instead of querying the reset counter before every access to the ring,
> query it the first time we touch the ring, and do a final compare when
> submitting the request. For correctness, we need to then sanitize how
> the reset_counter is incremented to prevent broken submission and
> waiting across resets, in the process fixing the persistent -EIO we
> still see today on failed waits.

tbh that explanation went straight over my head. Questions:
- Where do we wait again over a reset? With all the wakeups we should
  catch them properly. I guess this needs the detailed scenario to help me
  out, since I have dim memories that there is something wrong ;-)

- What precisely is the effect for waiters? I only see moving the
  atomic_inc under the dev->struct_mutex, which shouldn't do a hole lot
  for anyone. Plus not returning -EAGAIN when reset_in_progress, which
  looks like it might result in missed wakeups and deadlocks with the
  reset work.

I /thought/ that the -EIO is from check_wedge in intel_ring_begin, but
that part seems essentially unchanged.

Aside from all that, shuffling the atomic_inc (if I can convince myself
that it's safe) to avoid the reload_in_reset hack looks like a good
improvement.

More confused comments below.
-Daniel

> v2: Rebase
> v3: Now with added testcase
> 
> Testcase: igt/gem_eio
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c     |  2 +-
>  drivers/gpu/drm/i915/i915_drv.c         | 32 +++++++-----
>  drivers/gpu/drm/i915/i915_drv.h         | 39 ++++++++++----
>  drivers/gpu/drm/i915/i915_gem.c         | 90 +++++++++++++++------------------
>  drivers/gpu/drm/i915/i915_irq.c         | 21 +-------
>  drivers/gpu/drm/i915/intel_display.c    | 10 ++--
>  drivers/gpu/drm/i915/intel_ringbuffer.c | 17 ++++---
>  7 files changed, 104 insertions(+), 107 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index d83f35c8df34..107711ec956f 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -4415,7 +4415,7 @@ i915_wedged_get(void *data, u64 *val)
>  	struct drm_device *dev = data;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	*val = atomic_read(&dev_priv->gpu_error.reset_counter);
> +	*val = i915_terminally_wedged(&dev_priv->gpu_error);

Don't we have a few tests left that look at this still?

>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index ffd99d27fac7..5838882e10a1 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -841,23 +841,31 @@ int i915_resume_legacy(struct drm_device *dev)
>  int i915_reset(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct i915_gpu_error *error = &dev_priv->gpu_error;
> +	unsigned reset_counter;
>  	bool simulated;
>  	int ret;
>  
>  	intel_reset_gt_powersave(dev);
>  
>  	mutex_lock(&dev->struct_mutex);
> +	atomic_clear_mask(I915_WEDGED, &error->reset_counter);
> +	reset_counter = atomic_inc_return(&error->reset_counter);

This publishes the reset-complete too early for the modeset code I think.
At least it crucially relies upon dev->struct_mutex serializing
everything in our driver, and I don't like to cement that assumption in
even more.

Why do we need to move that atomic_inc again?

I guess what we could try is set it right after we've reset the hw, but
before we start to re-initialize it. So move the atomic stuff below
intel_gpu_reset, with some neat barrier again. Maybe we should even push
i915_gem_reset down below that too. Not sure.

> +	if (WARN_ON(__i915_reset_in_progress(reset_counter))) {
> +		ret = -EIO;
> +		goto error;
> +	}
>  
>  	i915_gem_reset(dev);
>  
> -	simulated = dev_priv->gpu_error.stop_rings != 0;
> +	simulated = error->stop_rings != 0;
>  
>  	ret = intel_gpu_reset(dev);
>  
>  	/* Also reset the gpu hangman. */
>  	if (simulated) {
>  		DRM_INFO("Simulated gpu hang, resetting stop_rings\n");
> -		dev_priv->gpu_error.stop_rings = 0;
> +		error->stop_rings = 0;
>  		if (ret == -ENODEV) {
>  			DRM_INFO("Reset not implemented, but ignoring "
>  				 "error for simulated gpu hangs\n");
> @@ -870,8 +878,7 @@ int i915_reset(struct drm_device *dev)
>  
>  	if (ret) {
>  		DRM_ERROR("Failed to reset chip: %i\n", ret);
> -		mutex_unlock(&dev->struct_mutex);
> -		return ret;
> +		goto error;
>  	}
>  
>  	intel_overlay_reset(dev_priv);
> @@ -890,20 +897,14 @@ int i915_reset(struct drm_device *dev)
>  	 * was running at the time of the reset (i.e. we weren't VT
>  	 * switched away).
>  	 */
> -
> -	/* Used to prevent gem_check_wedged returning -EAGAIN during gpu reset */
> -	dev_priv->gpu_error.reload_in_reset = true;
> -
>  	ret = i915_gem_init_hw(dev);
> -
> -	dev_priv->gpu_error.reload_in_reset = false;
> -
> -	mutex_unlock(&dev->struct_mutex);
>  	if (ret) {
>  		DRM_ERROR("Failed hw init on reset %d\n", ret);
> -		return ret;
> +		goto error;
>  	}
>  
> +	mutex_unlock(&dev->struct_mutex);
> +
>  	/*
>  	 * rps/rc6 re-init is necessary to restore state lost after the
>  	 * reset and the re-install of gt irqs. Skip for ironlake per
> @@ -914,6 +915,11 @@ int i915_reset(struct drm_device *dev)
>  		intel_enable_gt_powersave(dev);
>  
>  	return 0;
> +
> +error:
> +	atomic_set_mask(I915_WEDGED, &error->reset_counter);
> +	mutex_unlock(&dev->struct_mutex);
> +	return ret;
>  }
>  
>  static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 3fe933e4e664..aa83b284cb2f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1395,9 +1395,6 @@ struct i915_gpu_error {
>  
>  	/* For missed irq/seqno simulation. */
>  	unsigned int test_irq_rings;
> -
> -	/* Used to prevent gem_check_wedged returning -EAGAIN during gpu reset   */
> -	bool reload_in_reset;
>  };
>  
>  enum modeset_restore {
> @@ -2157,6 +2154,7 @@ struct drm_i915_gem_request {
>  	/** On Which ring this request was generated */
>  	struct drm_i915_private *i915;
>  	struct intel_engine_cs *engine;
> +	unsigned reset_counter;
>  
>  	/** GEM sequence number associated with this request. */
>  	uint32_t seqno;
> @@ -2891,23 +2889,47 @@ struct drm_i915_gem_request *
>  i915_gem_find_active_request(struct intel_engine_cs *ring);
>  
>  bool i915_gem_retire_requests(struct drm_device *dev);
> -int __must_check i915_gem_check_wedge(struct i915_gpu_error *error,
> +int __must_check i915_gem_check_wedge(unsigned reset_counter,
>  				      bool interruptible);
>  
> +static inline u32 i915_reset_counter(struct i915_gpu_error *error)
> +{
> +	return atomic_read(&error->reset_counter);
> +}
> +
> +static inline bool __i915_reset_in_progress(u32 reset)
> +{
> +	return unlikely(reset & I915_RESET_IN_PROGRESS_FLAG);
> +}
> +
> +static inline bool __i915_reset_in_progress_or_wedged(u32 reset)
> +{
> +	return unlikely(reset & (I915_RESET_IN_PROGRESS_FLAG | I915_WEDGED));
> +}
> +
> +static inline bool __i915_terminally_wedged(u32 reset)
> +{
> +	return unlikely(reset & I915_WEDGED);
> +}
> +
>  static inline bool i915_reset_in_progress(struct i915_gpu_error *error)
>  {
> -	return unlikely(atomic_read(&error->reset_counter)
> -			& (I915_RESET_IN_PROGRESS_FLAG | I915_WEDGED));
> +	return __i915_reset_in_progress(i915_reset_counter(error));
> +}
> +
> +static inline bool i915_reset_in_progress_or_wedged(struct i915_gpu_error *error)
> +{
> +	return __i915_reset_in_progress_or_wedged(i915_reset_counter(error));
>  }
>  
>  static inline bool i915_terminally_wedged(struct i915_gpu_error *error)
>  {
> -	return atomic_read(&error->reset_counter) & I915_WEDGED;
> +	return __i915_terminally_wedged(i915_reset_counter(error));
>  }
>  
>  static inline u32 i915_reset_count(struct i915_gpu_error *error)
>  {
> -	return ((atomic_read(&error->reset_counter) & ~I915_WEDGED) + 1) / 2;
> +	return ((i915_reset_counter(error) & ~I915_WEDGED) + 1) / 2;
>  }
>  
>  static inline bool i915_stop_ring_allow_ban(struct drm_i915_private *dev_priv)
> @@ -2940,7 +2962,6 @@ void __i915_add_request(struct drm_i915_gem_request *req,
>  #define i915_add_request_no_flush(req) \
>  	__i915_add_request(req, NULL, false)
>  int __i915_wait_request(struct drm_i915_gem_request *req,
> -			unsigned reset_counter,
>  			bool interruptible,
>  			s64 *timeout,
>  			struct intel_rps_client *rps);
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index d3609e111647..6ac9c80244fa 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -85,9 +85,7 @@ i915_gem_wait_for_error(struct i915_gpu_error *error)
>  {
>  	int ret;
>  
> -#define EXIT_COND (!i915_reset_in_progress(error) || \
> -		   i915_terminally_wedged(error))
> -	if (EXIT_COND)
> +	if (!i915_reset_in_progress(error))
>  		return 0;
>  
>  	/*
> @@ -96,17 +94,16 @@ i915_gem_wait_for_error(struct i915_gpu_error *error)
>  	 * we should simply try to bail out and fail as gracefully as possible.
>  	 */
>  	ret = wait_event_interruptible_timeout(error->reset_queue,
> -					       EXIT_COND,
> +					       !i915_reset_in_progress(error),
>  					       10*HZ);
>  	if (ret == 0) {
>  		DRM_ERROR("Timed out waiting for the gpu reset to complete\n");
>  		return -EIO;
>  	} else if (ret < 0) {
>  		return ret;
> +	} else {
> +		return 0;
>  	}
> -#undef EXIT_COND
> -
> -	return 0;

I like the existing color better ;-)

>  }
>  
>  int i915_mutex_lock_interruptible(struct drm_device *dev)
> @@ -1112,26 +1109,20 @@ put_rpm:
>  }
>  
>  int
> -i915_gem_check_wedge(struct i915_gpu_error *error,
> +i915_gem_check_wedge(unsigned reset_counter,
>  		     bool interruptible)
>  {
> -	if (i915_reset_in_progress(error)) {
> +	if (__i915_reset_in_progress_or_wedged(reset_counter)) {
>  		/* Non-interruptible callers can't handle -EAGAIN, hence return
>  		 * -EIO unconditionally for these. */
>  		if (!interruptible)
>  			return -EIO;
>  
>  		/* Recovery complete, but the reset failed ... */
> -		if (i915_terminally_wedged(error))
> +		if (__i915_terminally_wedged(reset_counter))
>  			return -EIO;
>  
> -		/*
> -		 * Check if GPU Reset is in progress - we need intel_ring_begin
> -		 * to work properly to reinit the hw state while the gpu is
> -		 * still marked as reset-in-progress. Handle this with a flag.
> -		 */
> -		if (!error->reload_in_reset)
> -			return -EAGAIN;
> +		return -EAGAIN;

This only works because you move the check_wedge from ring_begin to
wait_space, so assumes that we never change that again. Rather fragile
imo.

>  	}
>  
>  	return 0;
> @@ -1200,7 +1191,6 @@ static int __i915_spin_request(struct drm_i915_gem_request *req, int state)
>  /**
>   * __i915_wait_request - wait until execution of request has finished
>   * @req: duh!
> - * @reset_counter: reset sequence associated with the given request
>   * @interruptible: do an interruptible wait (normally yes)
>   * @timeout: in - how long to wait (NULL forever); out - how much time remaining
>   *
> @@ -1215,7 +1205,6 @@ static int __i915_spin_request(struct drm_i915_gem_request *req, int state)
>   * errno with remaining time filled in timeout argument.
>   */
>  int __i915_wait_request(struct drm_i915_gem_request *req,
> -			unsigned reset_counter,
>  			bool interruptible,
>  			s64 *timeout,
>  			struct intel_rps_client *rps)
> @@ -1264,12 +1253,12 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
>  
>  		/* We need to check whether any gpu reset happened in between
>  		 * the caller grabbing the seqno and now ... */
> -		if (reset_counter != atomic_read(&dev_priv->gpu_error.reset_counter)) {
> -			/* ... but upgrade the -EAGAIN to an -EIO if the gpu
> -			 * is truely gone. */
> -			ret = i915_gem_check_wedge(&dev_priv->gpu_error, interruptible);
> -			if (ret == 0)
> -				ret = -EAGAIN;
> +		if (req->reset_counter != i915_reset_counter(&dev_priv->gpu_error)) {
> +			/* As we do not requeue the request over a GPU reset,
> +			 * if one does occur we know that the request is
> +			 * effectively complete.
> +			 */
> +			ret = 0;
>  			break;

This now no longer bails out straight when a reset is in progress with
-EAGAIN. I fear for the deadlocks.

>  		}
>  
> @@ -1433,13 +1422,7 @@ i915_wait_request(struct drm_i915_gem_request *req)
>  
>  	BUG_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));
>  
> -	ret = i915_gem_check_wedge(&dev_priv->gpu_error, interruptible);
> -	if (ret)
> -		return ret;
> -
> -	ret = __i915_wait_request(req,
> -				  atomic_read(&dev_priv->gpu_error.reset_counter),
> -				  interruptible, NULL, NULL);
> +	ret = __i915_wait_request(req, interruptible, NULL, NULL);
>  	if (ret)
>  		return ret;
>  
> @@ -1514,7 +1497,6 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj,
>  	struct drm_device *dev = obj->base.dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct drm_i915_gem_request *requests[I915_NUM_RINGS];
> -	unsigned reset_counter;
>  	int ret, i, n = 0;
>  
>  	BUG_ON(!mutex_is_locked(&dev->struct_mutex));
> @@ -1523,12 +1505,6 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj,
>  	if (!obj->active)
>  		return 0;
>  
> -	ret = i915_gem_check_wedge(&dev_priv->gpu_error, true);
> -	if (ret)
> -		return ret;
> -
> -	reset_counter = atomic_read(&dev_priv->gpu_error.reset_counter);
> -
>  	if (readonly) {
>  		struct drm_i915_gem_request *req;
>  
> @@ -1550,9 +1526,9 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj,
>  	}
>  
>  	mutex_unlock(&dev->struct_mutex);
> +	ret = 0;
>  	for (i = 0; ret == 0 && i < n; i++)
> -		ret = __i915_wait_request(requests[i], reset_counter, true,
> -					  NULL, rps);
> +		ret = __i915_wait_request(requests[i], true, NULL, rps);
>  	mutex_lock(&dev->struct_mutex);
>  
>  	for (i = 0; i < n; i++) {
> @@ -2707,6 +2683,7 @@ int i915_gem_request_alloc(struct intel_engine_cs *engine,
>  			   struct drm_i915_gem_request **req_out)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(engine->dev);
> +	unsigned reset_counter = i915_reset_counter(&dev_priv->gpu_error);
>  	struct drm_i915_gem_request *req;
>  	int ret;
>  
> @@ -2715,6 +2692,10 @@ int i915_gem_request_alloc(struct intel_engine_cs *engine,
>  
>  	*req_out = NULL;
>  
> +	ret = i915_gem_check_wedge(reset_counter, dev_priv->mm.interruptible);
> +	if (ret)
> +		return ret;
> +
>  	req = kmem_cache_zalloc(dev_priv->requests, GFP_KERNEL);
>  	if (req == NULL)
>  		return -ENOMEM;
> @@ -2725,6 +2706,7 @@ int i915_gem_request_alloc(struct intel_engine_cs *engine,
>  
>  	kref_init(&req->ref);
>  	req->i915 = dev_priv;
> +	req->reset_counter = reset_counter;
>  	req->engine = engine;
>  	req->ctx  = ctx;
>  	i915_gem_context_reference(req->ctx);
> @@ -3077,11 +3059,9 @@ void i915_gem_close_object(struct drm_gem_object *gem,
>  int
>  i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>  {
> -	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct drm_i915_gem_wait *args = data;
>  	struct drm_i915_gem_object *obj;
>  	struct drm_i915_gem_request *req[I915_NUM_RINGS];
> -	unsigned reset_counter;
>  	int i, n = 0;
>  	int ret;
>  
> @@ -3115,7 +3095,6 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>  	}
>  
>  	drm_gem_object_unreference(&obj->base);
> -	reset_counter = atomic_read(&dev_priv->gpu_error.reset_counter);
>  
>  	for (i = 0; i < I915_NUM_RINGS; i++) {
>  		if (obj->last_read_req[i] == NULL)
> @@ -3128,11 +3107,23 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>  
>  	for (i = 0; i < n; i++) {
>  		if (ret == 0)
> -			ret = __i915_wait_request(req[i], reset_counter, true,
> +			ret = __i915_wait_request(req[i], true,
>  						  args->timeout_ns > 0 ? &args->timeout_ns : NULL,
>  						  file->driver_priv);
> +
> +		/* If the GPU hung before this, report it. Ideally we only
> +		 * report if this request cannot be completed. Currently
> +		 * when we don't mark the guilty party and abort all
> +		 * requests on reset, so just mark all as EIO.
> +		 */
> +		if (ret == 0 &&
> +		    req[i]->reset_counter != i915_reset_counter(&req[i]->i915->gpu_error))
> +			ret = -EIO;
> +
>  		i915_gem_request_unreference__unlocked(req[i]);
>  	}
> +
> +
>  	return ret;
>  
>  out:
> @@ -3160,7 +3151,6 @@ __i915_gem_object_sync(struct drm_i915_gem_object *obj,
>  	if (!i915_semaphore_is_enabled(from_req->i915)) {
>  		struct drm_i915_private *i915 = from_req->i915;
>  		ret = __i915_wait_request(from_req,
> -					  atomic_read(&i915->gpu_error.reset_counter),
>  					  i915->mm.interruptible,
>  					  NULL,
>  					  &i915->rps.semaphores);
> @@ -4082,14 +4072,15 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
>  	struct drm_i915_file_private *file_priv = file->driver_priv;
>  	unsigned long recent_enough = jiffies - DRM_I915_THROTTLE_JIFFIES;
>  	struct drm_i915_gem_request *request, *target = NULL;
> -	unsigned reset_counter;
>  	int ret;
>  
>  	ret = i915_gem_wait_for_error(&dev_priv->gpu_error);
>  	if (ret)
>  		return ret;
>  
> -	ret = i915_gem_check_wedge(&dev_priv->gpu_error, false);
> +	/* ABI: return -EIO if wedged */
> +	ret = i915_gem_check_wedge(i915_reset_counter(&dev_priv->gpu_error),
> +				   false);
>  	if (ret)
>  		return ret;
>  
> @@ -4107,7 +4098,6 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
>  
>  		target = request;
>  	}
> -	reset_counter = atomic_read(&dev_priv->gpu_error.reset_counter);
>  	if (target)
>  		i915_gem_request_reference(target);
>  	spin_unlock(&file_priv->mm.lock);
> @@ -4115,7 +4105,7 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
>  	if (target == NULL)
>  		return 0;
>  
> -	ret = __i915_wait_request(target, reset_counter, true, NULL, NULL);
> +	ret = __i915_wait_request(target, true, NULL, NULL);
>  	if (ret == 0)
>  		queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, 0);
>  
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index f9f5e9cf7360..186315208462 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2200,7 +2200,6 @@ static void i915_error_wake_up(struct drm_i915_private *dev_priv,
>  static void i915_reset_and_wakeup(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(dev);
> -	struct i915_gpu_error *error = &dev_priv->gpu_error;
>  	char *error_event[] = { I915_ERROR_UEVENT "=1", NULL };
>  	char *reset_event[] = { I915_RESET_UEVENT "=1", NULL };
>  	char *reset_done_event[] = { I915_ERROR_UEVENT "=0", NULL };
> @@ -2218,7 +2217,7 @@ static void i915_reset_and_wakeup(struct drm_device *dev)
>  	 * the reset in-progress bit is only ever set by code outside of this
>  	 * work we don't need to worry about any other races.
>  	 */
> -	if (i915_reset_in_progress(error) && !i915_terminally_wedged(error)) {
> +	if (i915_reset_in_progress(&dev_priv->gpu_error)) {
>  		DRM_DEBUG_DRIVER("resetting chip\n");
>  		kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE,
>  				   reset_event);
> @@ -2246,25 +2245,9 @@ static void i915_reset_and_wakeup(struct drm_device *dev)
>  
>  		intel_runtime_pm_put(dev_priv);
>  
> -		if (ret == 0) {
> -			/*
> -			 * After all the gem state is reset, increment the reset
> -			 * counter and wake up everyone waiting for the reset to
> -			 * complete.
> -			 *
> -			 * Since unlock operations are a one-sided barrier only,
> -			 * we need to insert a barrier here to order any seqno
> -			 * updates before
> -			 * the counter increment.
> -			 */
> -			smp_mb__before_atomic();
> -			atomic_inc(&dev_priv->gpu_error.reset_counter);
> -
> +		if (ret == 0)
>  			kobject_uevent_env(&dev->primary->kdev->kobj,
>  					   KOBJ_CHANGE, reset_done_event);
> -		} else {
> -			atomic_set_mask(I915_WEDGED, &error->reset_counter);
> -		}
>  
>  		/*
>  		 * Note: The wake_up also serves as a memory barrier so that
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index cdd6074257af..8cb89320d28d 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3298,8 +3298,7 @@ static bool intel_crtc_has_pending_flip(struct drm_crtc *crtc)
>  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
>  	bool pending;
>  
> -	if (i915_reset_in_progress(&dev_priv->gpu_error) ||
> -	    intel_crtc->reset_counter != atomic_read(&dev_priv->gpu_error.reset_counter))
> +	if (intel_crtc->reset_counter != i915_reset_counter(&dev_priv->gpu_error))
>  		return false;
>  
>  	spin_lock_irq(&dev->event_lock);
> @@ -10751,8 +10750,7 @@ static bool page_flip_finished(struct intel_crtc *crtc)
>  	struct drm_device *dev = crtc->base.dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	if (i915_reset_in_progress(&dev_priv->gpu_error) ||
> -	    crtc->reset_counter != atomic_read(&dev_priv->gpu_error.reset_counter))
> +	if (crtc->reset_counter != i915_reset_counter(&dev_priv->gpu_error))
>  		return true;
>  
>  	/*
> @@ -11180,9 +11178,7 @@ static void intel_mmio_flip_work_func(struct work_struct *work)
>  		container_of(work, struct intel_mmio_flip, work);
>  
>  	if (mmio_flip->req)
> -		WARN_ON(__i915_wait_request(mmio_flip->req,
> -					    mmio_flip->crtc->reset_counter,
> -					    false, NULL,
> +		WARN_ON(__i915_wait_request(mmio_flip->req, false, NULL,
>  					    &mmio_flip->i915->rps.mmioflips));
>  
>  	intel_do_mmio_flip(mmio_flip->crtc);
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index f33db3495e35..b3538b66353b 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -2156,9 +2156,7 @@ int intel_ring_idle(struct intel_engine_cs *ring)
>  			list);
>  
>  	/* Make sure we do not trigger any retires */
> -	return __i915_wait_request(req,
> -				   atomic_read(&req->i915->gpu_error.reset_counter),
> -				   req->i915->mm.interruptible,
> +	return __i915_wait_request(req, req->i915->mm.interruptible,
>  				   NULL, NULL);
>  }
>  
> @@ -2252,6 +2250,14 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
>  	if (ret)
>  		return ret;
>  
> +	/* If the request was completed due to a GPU hang, we want to
> +	 * error out before we continue to emit more commands to the GPU.
> +	 */
> +	ret = i915_gem_check_wedge(i915_reset_counter(&to_i915(engine->dev)->gpu_error),
> +				   to_i915(engine->dev)->mm.interruptible);
> +	if (ret)
> +		return ret;

Don't we still have the problem with -EIO now here, just less likely than
from intel_ring_begin?

> +
>  	ring->space = space;
>  	return 0;
>  }
> @@ -2316,11 +2322,6 @@ int intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
>  {
>  	int ret;
>  
> -	ret = i915_gem_check_wedge(&req->i915->gpu_error,
> -				   req->i915->mm.interruptible);
> -	if (ret)
> -		return ret;
> -
>  	ret = ring_prepare(req, num_dwords * sizeof(uint32_t));
>  	if (ret)
>  		return ret;
> -- 
> 2.6.2
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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