Subversion Repositories Kolibri OS

/*

 * Copyright © 2015 Intel Corporation

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include 

#include 

#include 

#include "i915_drv.h"

#include "intel_drv.h"

/**

 * DOC: Hotplug

 *

 * Simply put, hotplug occurs when a display is connected to or disconnected

 * from the system. However, there may be adapters and docking stations and

 * Display Port short pulses and MST devices involved, complicating matters.

 *

 * Hotplug in i915 is handled in many different levels of abstraction.

 *

 * The platform dependent interrupt handling code in i915_irq.c enables,

 * disables, and does preliminary handling of the interrupts. The interrupt

 * handlers gather the hotplug detect (HPD) information from relevant registers

 * into a platform independent mask of hotplug pins that have fired.

 *

 * The platform independent interrupt handler intel_hpd_irq_handler() in

 * intel_hotplug.c does hotplug irq storm detection and mitigation, and passes

 * further processing to appropriate bottom halves (Display Port specific and

 * regular hotplug).

 *

 * The Display Port work function i915_digport_work_func() calls into

 * intel_dp_hpd_pulse() via hooks, which handles DP short pulses and DP MST long

 * pulses, with failures and non-MST long pulses triggering regular hotplug

 * processing on the connector.

 *

 * The regular hotplug work function i915_hotplug_work_func() calls connector

 * detect hooks, and, if connector status changes, triggers sending of hotplug

 * uevent to userspace via drm_kms_helper_hotplug_event().

 *

 * Finally, the userspace is responsible for triggering a modeset upon receiving

 * the hotplug uevent, disabling or enabling the crtc as needed.

 *

 * The hotplug interrupt storm detection and mitigation code keeps track of the

 * number of interrupts per hotplug pin per a period of time, and if the number

 * of interrupts exceeds a certain threshold, the interrupt is disabled for a

 * while before being re-enabled. The intention is to mitigate issues raising

 * from broken hardware triggering massive amounts of interrupts and grinding

 * the system to a halt.

 *

 * Current implementation expects that hotplug interrupt storm will not be

 * seen when display port sink is connected, hence on platforms whose DP

 * callback is handled by i915_digport_work_func reenabling of hpd is not

 * performed (it was never expected to be disabled in the first place ;) )

 * this is specific to DP sinks handled by this routine and any other display

 * such as HDMI or DVI enabled on the same port will have proper logic since

 * it will use i915_hotplug_work_func where this logic is handled.

 */

bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port)

{

	switch (pin) {

	case HPD_PORT_A:

		*port = PORT_A;

		return true;

	case HPD_PORT_B:

		*port = PORT_B;

		return true;

	case HPD_PORT_C:

		*port = PORT_C;

		return true;

	case HPD_PORT_D:

		*port = PORT_D;

		return true;

	case HPD_PORT_E:

		*port = PORT_E;

		return true;

	default:

		return false;	/* no hpd */

	}

}

#define HPD_STORM_DETECT_PERIOD		1000

#define HPD_STORM_THRESHOLD		5

#define HPD_STORM_REENABLE_DELAY	(2 * 60 * 1000)

/**

 * intel_hpd_irq_storm_detect - gather stats and detect HPD irq storm on a pin

 * @dev_priv: private driver data pointer

 * @pin: the pin to gather stats on

 *

 * Gather stats about HPD irqs from the specified @pin, and detect irq

 * storms. Only the pin specific stats and state are changed, the caller is

 * responsible for further action.

 *

 * @HPD_STORM_THRESHOLD irqs are allowed within @HPD_STORM_DETECT_PERIOD ms,

 * otherwise it's considered an irq storm, and the irq state is set to

 * @HPD_MARK_DISABLED.

 *

 * Return true if an irq storm was detected on @pin.

 */

static bool intel_hpd_irq_storm_detect(struct drm_i915_private *dev_priv,

				       enum hpd_pin pin)

{

	unsigned long start = dev_priv->hotplug.stats[pin].last_jiffies;

	unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);

	bool storm = false;

	if (!time_in_range(jiffies, start, end)) {

		dev_priv->hotplug.stats[pin].last_jiffies = jiffies;

		dev_priv->hotplug.stats[pin].count = 0;

		DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: 0\n", pin);

	} else if (dev_priv->hotplug.stats[pin].count > HPD_STORM_THRESHOLD) {

		dev_priv->hotplug.stats[pin].state = HPD_MARK_DISABLED;

		DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);

		storm = true;

	} else {

		dev_priv->hotplug.stats[pin].count++;

		DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,

			      dev_priv->hotplug.stats[pin].count);

	}

	return storm;

}

static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)

{

	struct drm_device *dev = dev_priv->dev;

	struct drm_mode_config *mode_config = &dev->mode_config;

	struct intel_connector *intel_connector;

	struct intel_encoder *intel_encoder;

	struct drm_connector *connector;

	enum hpd_pin pin;

	bool hpd_disabled = false;

	assert_spin_locked(&dev_priv->irq_lock);

	list_for_each_entry(connector, &mode_config->connector_list, head) {

		if (connector->polled != DRM_CONNECTOR_POLL_HPD)

			continue;

		intel_connector = to_intel_connector(connector);

		intel_encoder = intel_connector->encoder;

		if (!intel_encoder)

			continue;

		pin = intel_encoder->hpd_pin;

		if (pin == HPD_NONE ||

		    dev_priv->hotplug.stats[pin].state != HPD_MARK_DISABLED)

			continue;

		DRM_INFO("HPD interrupt storm detected on connector %s: "

			 "switching from hotplug detection to polling\n",

			 connector->name);

		dev_priv->hotplug.stats[pin].state = HPD_DISABLED;

		connector->polled = DRM_CONNECTOR_POLL_CONNECT

			| DRM_CONNECTOR_POLL_DISCONNECT;

		hpd_disabled = true;

	}

	/* Enable polling and queue hotplug re-enabling. */

	if (hpd_disabled) {

		drm_kms_helper_poll_enable_locked(dev);

		mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,

				 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));

	}

}

static void intel_hpd_irq_storm_reenable_work(struct work_struct *work)

{

	struct drm_i915_private *dev_priv =

		container_of(work, typeof(*dev_priv),

			     hotplug.reenable_work.work);

	struct drm_device *dev = dev_priv->dev;

	struct drm_mode_config *mode_config = &dev->mode_config;

	int i;

	intel_runtime_pm_get(dev_priv);

	spin_lock_irq(&dev_priv->irq_lock);

	for_each_hpd_pin(i) {

		struct drm_connector *connector;

		if (dev_priv->hotplug.stats[i].state != HPD_DISABLED)

			continue;

		dev_priv->hotplug.stats[i].state = HPD_ENABLED;

		list_for_each_entry(connector, &mode_config->connector_list, head) {

			struct intel_connector *intel_connector = to_intel_connector(connector);

			if (intel_connector->encoder->hpd_pin == i) {

				if (connector->polled != intel_connector->polled)

					DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",

							 connector->name);

				connector->polled = intel_connector->polled;

				if (!connector->polled)

					connector->polled = DRM_CONNECTOR_POLL_HPD;

			}

		}

	}

	if (dev_priv->display.hpd_irq_setup)

		dev_priv->display.hpd_irq_setup(dev);

	spin_unlock_irq(&dev_priv->irq_lock);

	intel_runtime_pm_put(dev_priv);

}

static bool intel_hpd_irq_event(struct drm_device *dev,

				struct drm_connector *connector)

{

	enum drm_connector_status old_status;

	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));

	old_status = connector->status;

	connector->status = connector->funcs->detect(connector, false);

	if (old_status == connector->status)

		return false;

	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",

		      connector->base.id,

		      connector->name,

		      drm_get_connector_status_name(old_status),

		      drm_get_connector_status_name(connector->status));

	return true;

}

static void i915_digport_work_func(struct work_struct *work)

{

	struct drm_i915_private *dev_priv =

		container_of(work, struct drm_i915_private, hotplug.dig_port_work);

	u32 long_port_mask, short_port_mask;

	struct intel_digital_port *intel_dig_port;

	int i;

	u32 old_bits = 0;

	spin_lock_irq(&dev_priv->irq_lock);

	long_port_mask = dev_priv->hotplug.long_port_mask;

	dev_priv->hotplug.long_port_mask = 0;

	short_port_mask = dev_priv->hotplug.short_port_mask;

	dev_priv->hotplug.short_port_mask = 0;

	spin_unlock_irq(&dev_priv->irq_lock);

	for (i = 0; i < I915_MAX_PORTS; i++) {

		bool valid = false;

		bool long_hpd = false;

		intel_dig_port = dev_priv->hotplug.irq_port[i];

		if (!intel_dig_port || !intel_dig_port->hpd_pulse)

			continue;

		if (long_port_mask & (1 << i))  {

			valid = true;

			long_hpd = true;

		} else if (short_port_mask & (1 << i))

			valid = true;

		if (valid) {

			enum irqreturn ret;

			ret = intel_dig_port->hpd_pulse(intel_dig_port, long_hpd);

			if (ret == IRQ_NONE) {

				/* fall back to old school hpd */

				old_bits |= (1 << intel_dig_port->base.hpd_pin);

			}

		}

	}

	if (old_bits) {

		spin_lock_irq(&dev_priv->irq_lock);

		dev_priv->hotplug.event_bits |= old_bits;

		spin_unlock_irq(&dev_priv->irq_lock);

		schedule_work(&dev_priv->hotplug.hotplug_work);

	}

}

/*

 * Handle hotplug events outside the interrupt handler proper.

 */

static void i915_hotplug_work_func(struct work_struct *work)

{

	struct drm_i915_private *dev_priv =

		container_of(work, struct drm_i915_private, hotplug.hotplug_work);

	struct drm_device *dev = dev_priv->dev;

	struct drm_mode_config *mode_config = &dev->mode_config;

	struct intel_connector *intel_connector;

	struct intel_encoder *intel_encoder;

	struct drm_connector *connector;

	bool changed = false;

	u32 hpd_event_bits;

	mutex_lock(&mode_config->mutex);

	DRM_DEBUG_KMS("running encoder hotplug functions\n");

	spin_lock_irq(&dev_priv->irq_lock);

	hpd_event_bits = dev_priv->hotplug.event_bits;

	dev_priv->hotplug.event_bits = 0;

	/* Disable hotplug on connectors that hit an irq storm. */

	intel_hpd_irq_storm_disable(dev_priv);

	spin_unlock_irq(&dev_priv->irq_lock);

	list_for_each_entry(connector, &mode_config->connector_list, head) {

		intel_connector = to_intel_connector(connector);

		if (!intel_connector->encoder)

			continue;

		intel_encoder = intel_connector->encoder;

		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {

			DRM_DEBUG_KMS("Connector %s (pin %i) received hotplug event.\n",

				      connector->name, intel_encoder->hpd_pin);

			if (intel_encoder->hot_plug)

				intel_encoder->hot_plug(intel_encoder);

			if (intel_hpd_irq_event(dev, connector))

				changed = true;

		}

	}

	mutex_unlock(&mode_config->mutex);

	if (changed)

		drm_kms_helper_hotplug_event(dev);

}

/**

 * intel_hpd_irq_handler - main hotplug irq handler

 * @dev: drm device

 * @pin_mask: a mask of hpd pins that have triggered the irq

 * @long_mask: a mask of hpd pins that may be long hpd pulses

 *

 * This is the main hotplug irq handler for all platforms. The platform specific

 * irq handlers call the platform specific hotplug irq handlers, which read and

 * decode the appropriate registers into bitmasks about hpd pins that have

 * triggered (@pin_mask), and which of those pins may be long pulses

 * (@long_mask). The @long_mask is ignored if the port corresponding to the pin

 * is not a digital port.

 *

 * Here, we do hotplug irq storm detection and mitigation, and pass further

 * processing to appropriate bottom halves.

 */

void intel_hpd_irq_handler(struct drm_device *dev,

			   u32 pin_mask, u32 long_mask)

{

	struct drm_i915_private *dev_priv = dev->dev_private;

	int i;

	enum port port;

	bool storm_detected = false;

	bool queue_dig = false, queue_hp = false;

	bool is_dig_port;

	if (!pin_mask)

		return;

	spin_lock(&dev_priv->irq_lock);

	for_each_hpd_pin(i) {

		if (!(BIT(i) & pin_mask))

			continue;

		is_dig_port = intel_hpd_pin_to_port(i, &port) &&

			      dev_priv->hotplug.irq_port[port];

		if (is_dig_port) {

			bool long_hpd = long_mask & BIT(i);

			DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),

					 long_hpd ? "long" : "short");

			/*

			 * For long HPD pulses we want to have the digital queue happen,

			 * but we still want HPD storm detection to function.

			 */

			queue_dig = true;

			if (long_hpd) {

				dev_priv->hotplug.long_port_mask |= (1 << port);

			} else {

				/* for short HPD just trigger the digital queue */

				dev_priv->hotplug.short_port_mask |= (1 << port);

				continue;

			}

		}

		if (dev_priv->hotplug.stats[i].state == HPD_DISABLED) {

			/*

			 * On GMCH platforms the interrupt mask bits only

			 * prevent irq generation, not the setting of the

			 * hotplug bits itself. So only WARN about unexpected

			 * interrupts on saner platforms.

			 */

			WARN_ONCE(!HAS_GMCH_DISPLAY(dev),

				  "Received HPD interrupt on pin %d although disabled\n", i);

			continue;

		}

		if (dev_priv->hotplug.stats[i].state != HPD_ENABLED)

			continue;

		if (!is_dig_port) {

			dev_priv->hotplug.event_bits |= BIT(i);

			queue_hp = true;

		}

		if (intel_hpd_irq_storm_detect(dev_priv, i)) {

			dev_priv->hotplug.event_bits &= ~BIT(i);

			storm_detected = true;

		}

	}

	if (storm_detected)

		dev_priv->display.hpd_irq_setup(dev);

	spin_unlock(&dev_priv->irq_lock);

	/*

	 * Our hotplug handler can grab modeset locks (by calling down into the

	 * fb helpers). Hence it must not be run on our own dev-priv->wq work

	 * queue for otherwise the flush_work in the pageflip code will

	 * deadlock.

	 */

	if (queue_dig)

		queue_work(dev_priv->hotplug.dp_wq, &dev_priv->hotplug.dig_port_work);

	if (queue_hp)

		schedule_work(&dev_priv->hotplug.hotplug_work);

}

/**

 * intel_hpd_init - initializes and enables hpd support

 * @dev_priv: i915 device instance

 *

 * This function enables the hotplug support. It requires that interrupts have

 * already been enabled with intel_irq_init_hw(). From this point on hotplug and

 * poll request can run concurrently to other code, so locking rules must be

 * obeyed.

 *

 * This is a separate step from interrupt enabling to simplify the locking rules

 * in the driver load and resume code.

 */

void intel_hpd_init(struct drm_i915_private *dev_priv)

{

	struct drm_device *dev = dev_priv->dev;

	struct drm_mode_config *mode_config = &dev->mode_config;

	struct drm_connector *connector;

	int i;

	for_each_hpd_pin(i) {

		dev_priv->hotplug.stats[i].count = 0;

		dev_priv->hotplug.stats[i].state = HPD_ENABLED;

	}

	list_for_each_entry(connector, &mode_config->connector_list, head) {

		struct intel_connector *intel_connector = to_intel_connector(connector);

		connector->polled = intel_connector->polled;

		/* MST has a dynamic intel_connector->encoder and it's reprobing

		 * is all handled by the MST helpers. */

		if (intel_connector->mst_port)

			continue;

		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_irq(&dev_priv->irq_lock);

	if (dev_priv->display.hpd_irq_setup)

		dev_priv->display.hpd_irq_setup(dev);

	spin_unlock_irq(&dev_priv->irq_lock);

}

void intel_hpd_init_work(struct drm_i915_private *dev_priv)

{

	INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);

	INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);

	INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,

			  intel_hpd_irq_storm_reenable_work);

}

void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)

{

	spin_lock_irq(&dev_priv->irq_lock);

	dev_priv->hotplug.long_port_mask = 0;

	dev_priv->hotplug.short_port_mask = 0;

	dev_priv->hotplug.event_bits = 0;

	spin_unlock_irq(&dev_priv->irq_lock);

	cancel_work_sync(&dev_priv->hotplug.dig_port_work);

	cancel_work_sync(&dev_priv->hotplug.hotplug_work);

	cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);

}