Commit b236d7c8 authored by Lyude's avatar Lyude Committed by Daniel Vetter

drm/i915/vlv: Disable HPD in valleyview_crt_detect_hotplug()

One of the things preventing us from using polling is the fact that
calling valleyview_crt_detect_hotplug() when there's a VGA cable
connected results in sending another hotplug. With polling enabled when
HPD is disabled, this results in a scenario like this:

- We enable power wells and reset the ADPA
- output_poll_exec does force probe on VGA, triggering a hpd
- HPD handler waits for poll to unlock dev->mode_config.mutex
- output_poll_exec shuts off the ADPA, unlocks dev->mode_config.mutex
- HPD handler runs, resets ADPA and brings us back to the start

This results in an endless irq storm getting sent from the ADPA
whenever a VGA connector gets detected in the middle of polling.

Somewhat based off of the "drm/i915: Disable CRT HPD around force
trigger" patch Ville Syrjälä sent a while back

Cc: stable@vger.kernel.org
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarLyude <cpaul@redhat.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 9504a892
......@@ -2957,6 +2957,8 @@ void intel_hpd_init(struct drm_i915_private *dev_priv);
void intel_hpd_init_work(struct drm_i915_private *dev_priv);
void intel_hpd_cancel_work(struct drm_i915_private *dev_priv);
bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port);
bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin);
void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin);
/* i915_irq.c */
static inline void i915_queue_hangcheck(struct drm_i915_private *dev_priv)
......
......@@ -329,10 +329,25 @@ static bool valleyview_crt_detect_hotplug(struct drm_connector *connector)
struct drm_device *dev = connector->dev;
struct intel_crt *crt = intel_attached_crt(connector);
struct drm_i915_private *dev_priv = to_i915(dev);
bool reenable_hpd;
u32 adpa;
bool ret;
u32 save_adpa;
/*
* Doing a force trigger causes a hpd interrupt to get sent, which can
* get us stuck in a loop if we're polling:
* - We enable power wells and reset the ADPA
* - output_poll_exec does force probe on VGA, triggering a hpd
* - HPD handler waits for poll to unlock dev->mode_config.mutex
* - output_poll_exec shuts off the ADPA, unlocks
* dev->mode_config.mutex
* - HPD handler runs, resets ADPA and brings us back to the start
*
* Just disable HPD interrupts here to prevent this
*/
reenable_hpd = intel_hpd_disable(dev_priv, crt->base.hpd_pin);
save_adpa = adpa = I915_READ(crt->adpa_reg);
DRM_DEBUG_KMS("trigger hotplug detect cycle: adpa=0x%x\n", adpa);
......@@ -357,6 +372,9 @@ static bool valleyview_crt_detect_hotplug(struct drm_connector *connector)
DRM_DEBUG_KMS("valleyview hotplug adpa=0x%x, result %d\n", adpa, ret);
if (reenable_hpd)
intel_hpd_enable(dev_priv, crt->base.hpd_pin);
return ret;
}
......
......@@ -510,3 +510,30 @@ void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
cancel_work_sync(&dev_priv->hotplug.hotplug_work);
cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
}
bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
{
bool ret = false;
if (pin == HPD_NONE)
return false;
spin_lock_irq(&dev_priv->irq_lock);
if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
ret = true;
}
spin_unlock_irq(&dev_priv->irq_lock);
return ret;
}
void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
{
if (pin == HPD_NONE)
return;
spin_lock_irq(&dev_priv->irq_lock);
dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
spin_unlock_irq(&dev_priv->irq_lock);
}
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