drm/i915: Error checks in gen6_set_rps
With the new "standardized" sysfs interfaces we need to be a bit more
careful about setting the RPS values.
Because the sysfs code and the rps workqueue can run at the same time,
if the sysfs setter wins the race to the mutex, the workqueue can come
in and set a value which is out of range (ie. we're no longer protecting
by RPINTLIM).
I was not able to actually make this error occur in testing.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index dd49046..d915126 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -382,7 +382,13 @@
else
new_delay = dev_priv->rps.cur_delay - 1;
- gen6_set_rps(dev_priv->dev, new_delay);
+ /* sysfs frequency interfaces may have snuck in while servicing the
+ * interrupt
+ */
+ if (!(new_delay > dev_priv->rps.max_delay ||
+ new_delay < dev_priv->rps.min_delay)) {
+ gen6_set_rps(dev_priv->dev, new_delay);
+ }
mutex_unlock(&dev_priv->dev->struct_mutex);
}