diff options
author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2013-06-27 15:52:15 (GMT) |
---|---|---|
committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2013-07-01 09:14:59 (GMT) |
commit | b5ea2d5681522f1b8ef886b5ac039903bf1d39fe (patch) | |
tree | 866e987e68aa8c973f02046eb29ad4abf2dd3639 /drivers/gpu/drm/i915 | |
parent | 91d131d21e4916f84e5957cc25bea6dd355dfe77 (diff) | |
download | linux-fsl-qoriq-b5ea2d5681522f1b8ef886b5ac039903bf1d39fe.tar.xz |
drm/i915: fix hpd interrupt register locking
Our interrupt handler (in hardirq context) could race with the timer
(in softirq context), hence we need to hold the spinlock around the
call to ->hdp_irq_setup in intel_hpd_irq_handler, too.
But as an optimization (and more so to clarify things) we don't need
to do the irqsave/restore dance in the hardirq context.
Note also that on ilk+ the race isn't just against the hotplug
reenable timer, but also against the fifo underrun reporting. That one
also modifies the SDEIMR register (again protected by the same
dev_priv->irq_lock).
To lock things down again sprinkle a assert_spin_locked. But exclude
the functions touching SDEIMR for now, I want to extract them all into
a new helper function (like we do already for pipestate, display
interrupts and all the various gt interrupts).
v2: Add the missing 't' Egbert spotted in a comment.
v3: Actually fix the right misspelled comment (Paulo).
Cc: Egbert Eich <eich@suse.de>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/i915')
-rw-r--r-- | drivers/gpu/drm/i915/i915_irq.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index b29b76f..3d92a7c 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -877,15 +877,13 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev, const u32 *hpd) { drm_i915_private_t *dev_priv = dev->dev_private; - unsigned long irqflags; int i; bool storm_detected = false; if (!hotplug_trigger) return; - spin_lock_irqsave(&dev_priv->irq_lock, irqflags); - + spin_lock(&dev_priv->irq_lock); for (i = 1; i < HPD_NUM_PINS; i++) { if (!(hpd[i] & hotplug_trigger) || @@ -908,10 +906,9 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev, } } - spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags); - if (storm_detected) dev_priv->display.hpd_irq_setup(dev); + spin_unlock(&dev_priv->irq_lock); queue_work(dev_priv->wq, &dev_priv->hotplug_work); @@ -3380,6 +3377,8 @@ static void i915_hpd_irq_setup(struct drm_device *dev) struct intel_encoder *intel_encoder; u32 hotplug_en; + assert_spin_locked(&dev_priv->irq_lock); + if (I915_HAS_HOTPLUG(dev)) { hotplug_en = I915_READ(PORT_HOTPLUG_EN); hotplug_en &= ~HOTPLUG_INT_EN_MASK; @@ -3663,6 +3662,7 @@ void intel_hpd_init(struct drm_device *dev) struct drm_i915_private *dev_priv = dev->dev_private; struct drm_mode_config *mode_config = &dev->mode_config; struct drm_connector *connector; + unsigned long irqflags; int i; for (i = 1; i < HPD_NUM_PINS; i++) { @@ -3675,6 +3675,11 @@ void intel_hpd_init(struct drm_device *dev) if (!connector->polled && I915_HAS_HOTPLUG(dev) && intel_connector->encoder->hpd_pin > HPD_NONE) connector->polled = DRM_CONNECTOR_POLL_HPD; } + + /* Interrupt setup is already guaranteed to be single-threaded, this is + * just to make the assert_spin_locked checks happy. */ + spin_lock_irqsave(&dev_priv->irq_lock, irqflags); if (dev_priv->display.hpd_irq_setup) dev_priv->display.hpd_irq_setup(dev); + spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags); } |