drm/i915: Replace wait-on-mutex with wait-on-bit in reset worker
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@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160909131201.16673-12-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index ff4173e..f2614b2 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1726,8 +1726,8 @@
* i915_reset - reset chip after a hang
* @dev: drm device to reset
*
- * Reset the chip. Useful if a hang is detected. Returns zero on successful
- * reset or otherwise an error code.
+ * Reset the chip. Useful if a hang is detected. Marks the device as wedged
+ * on failure.
*
* Caller must hold the struct_mutex.
*
@@ -1739,7 +1739,7 @@
* - re-init interrupt state
* - re-init display
*/
-int i915_reset(struct drm_i915_private *dev_priv)
+void i915_reset(struct drm_i915_private *dev_priv)
{
struct drm_device *dev = &dev_priv->drm;
struct i915_gpu_error *error = &dev_priv->gpu_error;
@@ -1748,7 +1748,7 @@
lockdep_assert_held(&dev->struct_mutex);
if (!test_and_clear_bit(I915_RESET_IN_PROGRESS, &error->flags))
- return test_bit(I915_WEDGED, &error->flags) ? -EIO : 0;
+ return;
/* Clear any previous failed attempts at recovery. Time to try again. */
__clear_bit(I915_WEDGED, &error->flags);
@@ -1798,11 +1798,13 @@
intel_sanitize_gt_powersave(dev_priv);
intel_autoenable_gt_powersave(dev_priv);
- return 0;
+wakeup:
+ wake_up_bit(&error->flags, I915_RESET_IN_PROGRESS);
+ return;
error:
set_bit(I915_WEDGED, &error->flags);
- return ret;
+ goto wakeup;
}
static int i915_pm_suspend(struct device *kdev)