Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

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

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

drivers/gpu/drm/i915/i915_drv.h

+2 −0
Original line number Diff line number Diff line
@@ -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)

drivers/gpu/drm/i915/intel_crt.c

+18 −0
Original line number Diff line number Diff line
@@ -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;

}

drivers/gpu/drm/i915/intel_hotplug.c

+27 −0
Original line number Diff line number Diff line
@@ -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);

}