From 792496368bcd766926239a5ad105ca9aad797b34 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Fri, 7 Sep 2012 19:43:42 -0700 Subject: [PATCH] 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 Reviewed-by: Chris Wilson Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_irq.c | 8 +++++++- drivers/gpu/drm/i915/intel_pm.c | 2 ++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index dd49046bccd1..d9151264d914 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -382,7 +382,13 @@ static void gen6_pm_rps_work(struct work_struct *work) 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); } diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 4e86037ae6b4..82ca172831c5 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -2324,6 +2324,8 @@ void gen6_set_rps(struct drm_device *dev, u8 val) u32 limits = gen6_rps_limits(dev_priv, &val); WARN_ON(!mutex_is_locked(&dev->struct_mutex)); + WARN_ON(val > dev_priv->rps.max_delay); + WARN_ON(val < dev_priv->rps.min_delay); if (val == dev_priv->rps.cur_delay) return; -- 2.34.1