33  * DOC: Hotplug
35  * Simply put, hotplug occurs when a display is connected to or disconnected
39  * Hotplug in i915 is handled in many different levels of abstraction.
43  * handlers gather the hotplug detect (HPD) information from relevant registers
44  * into a platform independent mask of hotplug pins that have fired.
47  * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes
49  * regular hotplug).
53  * pulses, with failures and non-MST long pulses triggering regular hotplug
56  * The regular hotplug work function i915_hotplug_work_func() calls connector
57  * detect hooks, and, if connector status changes, triggers sending of hotplug
61  * the hotplug uevent, disabling or enabling the crtc as needed.
63  * The hotplug interrupt storm detection and mitigation code keeps track of the
64  * number of interrupts per hotplug pin per a period of time, and if the number
70  * Current implementation expects that hotplug interrupt storm will not be
126  * stored in @dev_priv->hotplug.hpd_storm_threshold which defaults to
131  * and should only be adjusted for automated hotplug testing.
138 	unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;  in intel_hpd_irq_storm_detect()
140 	const int threshold = dev_priv->hotplug.hpd_storm_threshold;  in intel_hpd_irq_storm_detect()
144 		dev_priv->hotplug.stats[pin].last_jiffies = jiffies;  in intel_hpd_irq_storm_detect()
145 		dev_priv->hotplug.stats[pin].count = 0;  in intel_hpd_irq_storm_detect()
147 	} else if (dev_priv->hotplug.stats[pin].count > threshold &&  in intel_hpd_irq_storm_detect()
149 		dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;  in intel_hpd_irq_storm_detect()
153 		dev_priv->hotplug.stats[pin].count++;  in intel_hpd_irq_storm_detect()
155 			      dev_priv->hotplug.stats[pin].count);  in intel_hpd_irq_storm_detect()
185 		    dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)  in intel_hpd_irq_storm_disable()
189 			 "switching from hotplug detection to polling\n",  in intel_hpd_irq_storm_disable()
192 		dev_priv->hotplug.stats[pin].state = HPD_DISABLED;  in intel_hpd_irq_storm_disable()
199 	/* Enable polling and queue hotplug re-enabling. */  in intel_hpd_irq_storm_disable()
202 		mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,  in intel_hpd_irq_storm_disable()
211 			     hotplug.reenable_work.work);  in intel_hpd_irq_storm_reenable_work()
222 		if (dev_priv->hotplug.stats[pin].state != HPD_DISABLED)  in intel_hpd_irq_storm_reenable_work()
225 		dev_priv->hotplug.stats[pin].state = HPD_ENABLED;  in intel_hpd_irq_storm_reenable_work()
284 		container_of(work, struct drm_i915_private, hotplug.dig_port_work);  in i915_digport_work_func()
290 	long_port_mask = dev_priv->hotplug.long_port_mask;  in i915_digport_work_func()
291 	dev_priv->hotplug.long_port_mask = 0;  in i915_digport_work_func()
292 	short_port_mask = dev_priv->hotplug.short_port_mask;  in i915_digport_work_func()
293 	dev_priv->hotplug.short_port_mask = 0;  in i915_digport_work_func()
322 		dev_priv->hotplug.event_bits |= old_bits;  in i915_digport_work_func()
324 		schedule_work(&dev_priv->hotplug.hotplug_work);  in i915_digport_work_func()
329  * Handle hotplug events outside the interrupt handler proper.
334 		container_of(work, struct drm_i915_private, hotplug.hotplug_work);  in i915_hotplug_work_func()
344 	DRM_DEBUG_KMS("running encoder hotplug functions\n");  in i915_hotplug_work_func()
348 	hpd_event_bits = dev_priv->hotplug.event_bits;  in i915_hotplug_work_func()
349 	dev_priv->hotplug.event_bits = 0;  in i915_hotplug_work_func()
351 	/* Disable hotplug on connectors that hit an irq storm. */  in i915_hotplug_work_func()
363 			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",  in i915_hotplug_work_func()
366 			changed |= intel_encoder->hotplug(intel_encoder,  in i915_hotplug_work_func()
379  * intel_hpd_irq_handler - main hotplug irq handler
384  * This is the main hotplug irq handler for all platforms. The platform specific
385  * irq handlers call the platform specific hotplug irq handlers, which read and
391  * Here, we do hotplug irq storm detection and mitigation, and pass further
435 			dev_priv->hotplug.long_port_mask |= BIT(port);  in intel_hpd_irq_handler()
438 			dev_priv->hotplug.short_port_mask |= BIT(port);  in intel_hpd_irq_handler()
449 		if (dev_priv->hotplug.stats[pin].state == HPD_DISABLED) {  in intel_hpd_irq_handler()
453 			 * hotplug bits itself. So only WARN about unexpected  in intel_hpd_irq_handler()
461 		if (dev_priv->hotplug.stats[pin].state != HPD_ENABLED)  in intel_hpd_irq_handler()
472 			dev_priv->hotplug.event_bits |= BIT(pin);  in intel_hpd_irq_handler()
481 			dev_priv->hotplug.event_bits &= ~BIT(pin);  in intel_hpd_irq_handler()
491 	 * Our hotplug handler can grab modeset locks (by calling down into the  in intel_hpd_irq_handler()
497 		queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);  in intel_hpd_irq_handler()
499 		schedule_work(&dev_priv->hotplug.hotplug_work);  in intel_hpd_irq_handler()
506  * This function enables the hotplug support. It requires that interrupts have
507  * already been enabled with intel_irq_init_hw(). From this point on hotplug and
521 		dev_priv->hotplug.stats[i].count = 0;  in intel_hpd_init()
522 		dev_priv->hotplug.stats[i].state = HPD_ENABLED;  in intel_hpd_init()
525 	WRITE_ONCE(dev_priv->hotplug.poll_enabled, false);  in intel_hpd_init()
526 	schedule_work(&dev_priv->hotplug.poll_init_work);  in intel_hpd_init()
544 			     hotplug.poll_init_work);  in i915_hpd_poll_init_work()
552 	enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);  in i915_hpd_poll_init_work()
593  * not they support hotplug detection. Under certain conditions HPD may not be
599  * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
606 	WRITE_ONCE(dev_priv->hotplug.poll_enabled, true);  in intel_hpd_poll_init()
614 	schedule_work(&dev_priv->hotplug.poll_init_work);  in intel_hpd_poll_init()
619 	INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);  in intel_hpd_init_work()
620 	INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);  in intel_hpd_init_work()
621 	INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);  in intel_hpd_init_work()
622 	INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,  in intel_hpd_init_work()
630 	dev_priv->hotplug.long_port_mask = 0;  in intel_hpd_cancel_work()
631 	dev_priv->hotplug.short_port_mask = 0;  in intel_hpd_cancel_work()
632 	dev_priv->hotplug.event_bits = 0;  in intel_hpd_cancel_work()
636 	cancel_work_sync(&dev_priv->hotplug.dig_port_work);  in intel_hpd_cancel_work()
637 	cancel_work_sync(&dev_priv->hotplug.hotplug_work);  in intel_hpd_cancel_work()
638 	cancel_work_sync(&dev_priv->hotplug.poll_init_work);  in intel_hpd_cancel_work()
639 	cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);  in intel_hpd_cancel_work()
650 	if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {  in intel_hpd_disable()
651 		dev_priv->hotplug.stats[pin].state = HPD_DISABLED;  in intel_hpd_disable()
665 	dev_priv->hotplug.stats[pin].state = HPD_ENABLED;  in intel_hpd_enable()