Since we have a cooperative mode now with a direct reset, we can avoid
the contention on struct_mutex and instead try then sleep on the
I915_RESET_IN_PROGRESS bit. If the mutex is held and that bit is
cleared, all is fine. Otherwise, we sleep for a bit and try again. In
the worst case we sleep for an extra second waiting for the mutex to be
released (no one touching the GPU is allowed the struct_mutex whilst the
I915_RESET_IN_PROGRESS bit is set). But when we have a direct reset,
this allows us to clean up the reset worker faster.
v2: Remember to call wake_up_bit() after changing (for the faster wakeup
as promised)
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.c | 6 ++++--
drivers/gpu/drm/i915/i915_irq.c | 30 ++++++++++++++++++------------
2 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index ff4173e6e298..c1b890dbd6cc 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1798,11 +1798,13 @@ int i915_reset(struct drm_i915_private *dev_priv)
intel_sanitize_gt_powersave(dev_priv);
intel_autoenable_gt_powersave(dev_priv);
- return 0;
+out:
+ wake_up_bit(&error->flags, I915_RESET_IN_PROGRESS);
+ return ret;
error:
set_bit(I915_WEDGED, &error->flags);
- return ret;
+ goto out;
}
static int i915_pm_suspend(struct device *kdev)
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2c7cb5041511..699ee2c7a3e4 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2497,7 +2497,7 @@ static void i915_reset_and_wakeup(struct drm_i915_private *dev_priv)
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 };
- int ret;
+ int ret = -EAGAIN;
kobject_uevent_env(kobj, KOBJ_CHANGE, error_event);
@@ -2512,21 +2512,27 @@ static void i915_reset_and_wakeup(struct drm_i915_private *dev_priv)
* simulated reset via debugs, so get an RPM reference.
*/
intel_runtime_pm_get(dev_priv);
-
intel_prepare_reset(dev_priv);
- /*
- * All state reset _must_ be completed before we update the
- * reset counter, for otherwise waiters might miss the reset
- * pending state and not properly drop locks, resulting in
- * deadlocks with the reset work.
- */
- mutex_lock(&dev_priv->drm.struct_mutex);
- ret = i915_reset(dev_priv);
- mutex_unlock(&dev_priv->drm.struct_mutex);
+ do {
+ /*
+ * All state reset _must_ be completed before we update the
+ * reset counter, for otherwise waiters might miss the reset
+ * pending state and not properly drop locks, resulting in
+ * deadlocks with the reset work.
+ */
+ if (mutex_trylock(&dev_priv->drm.struct_mutex)) {
+ ret = i915_reset(dev_priv);
+ mutex_unlock(&dev_priv->drm.struct_mutex);
+ }
- intel_finish_reset(dev_priv);
+ /* We need to wait for anyone holding the lock to wakeup */
+ } while (wait_on_bit_timeout(&dev_priv->gpu_error.flags,
+ I915_RESET_IN_PROGRESS,
+ TASK_UNINTERRUPTIBLE,
+ HZ));
+ intel_finish_reset(dev_priv);
intel_runtime_pm_put(dev_priv);
if (ret == 0)
--
2.9.3
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