Commit d5367307 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Wait for concurrent global resets to complete 



If we enter i915_handle_error() a second time and a global reset is
already in progress, we can simply wait for completion of the first
reset. Currently we exit early prior to the actual reset being
performed -- the worst of both worlds!

v2: Plug into the existing reset_queue, and remember that kselftests is
playing games with I915_RESET_BACKOFF to prevent hangcheck from screwing
up.
v3: Rename to i915_reset_device to fit in better with i915_reset_engine

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: default avatarMichel Thierry <michel.thierry@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170620095751.13127-2-chris@chris-wilson.co.uk
parent 1acfc104

drivers/gpu/drm/i915/i915_irq.c

+11 −12
Original line number Diff line number Diff line
@@ -2600,13 +2600,13 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg) 
}



/**

 * i915_reset_and_wakeup - do process context error handling work

 * i915_reset_device - do process context error handling work

 * @dev_priv: i915 device private

 *

 * Fire an error uevent so userspace can see that a hang or error

 * was detected.

 */

static void i915_reset_and_wakeup(struct drm_i915_private *dev_priv)

static void i915_reset_device(struct drm_i915_private *dev_priv)

{

	struct kobject *kobj = &dev_priv->drm.primary->kdev->kobj;

	char *error_event[] = { I915_ERROR_UEVENT "=1", NULL };
@@ -2646,13 +2646,6 @@ static void i915_reset_and_wakeup(struct drm_i915_private *dev_priv) 
	if (!test_bit(I915_WEDGED, &dev_priv->gpu_error.flags))

		kobject_uevent_env(kobj,

				   KOBJ_CHANGE, reset_done_event);



	/*

	 * Note: The wake_up also serves as a memory barrier so that

	 * waiters see the updated value of the dev_priv->gpu_error.

	 */

	clear_bit(I915_RESET_BACKOFF, &dev_priv->gpu_error.flags);

	wake_up_all(&dev_priv->gpu_error.reset_queue);

}



static inline void
@@ -2744,11 +2737,17 @@ void i915_handle_error(struct drm_i915_private *dev_priv, 
	if (!engine_mask)

		goto out;



	if (test_and_set_bit(I915_RESET_BACKOFF,

			     &dev_priv->gpu_error.flags))

	if (test_and_set_bit(I915_RESET_BACKOFF, &dev_priv->gpu_error.flags)) {

		wait_event(dev_priv->gpu_error.reset_queue,

			   !test_bit(I915_RESET_BACKOFF,

				     &dev_priv->gpu_error.flags));

		goto out;

	}



	i915_reset_device(dev_priv);



	i915_reset_and_wakeup(dev_priv);

	clear_bit(I915_RESET_BACKOFF, &dev_priv->gpu_error.flags);

	wake_up_all(&dev_priv->gpu_error.reset_queue);



out:

	intel_runtime_pm_put(dev_priv);

drivers/gpu/drm/i915/selftests/intel_hangcheck.c

+4 −0
Original line number Diff line number Diff line
@@ -316,6 +316,8 @@ static int igt_global_reset(void *arg) 


	GEM_BUG_ON(test_bit(I915_RESET_HANDOFF, &i915->gpu_error.flags));

	clear_bit(I915_RESET_BACKOFF, &i915->gpu_error.flags);

	wake_up_all(&i915->gpu_error.reset_queue);



	if (i915_terminally_wedged(&i915->gpu_error))

		err = -EIO;
@@ -404,6 +406,7 @@ fini: 
unlock:

	mutex_unlock(&i915->drm.struct_mutex);

	clear_bit(I915_RESET_BACKOFF, &i915->gpu_error.flags);

	wake_up_all(&i915->gpu_error.reset_queue);



	if (i915_terminally_wedged(&i915->gpu_error))

		return -EIO;
@@ -519,6 +522,7 @@ fini: 
unlock:

	mutex_unlock(&i915->drm.struct_mutex);

	clear_bit(I915_RESET_BACKOFF, &i915->gpu_error.flags);

	wake_up_all(&i915->gpu_error.reset_queue);



	if (i915_terminally_wedged(&i915->gpu_error))

		return -EIO;

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