/* * 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->drm; 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->drm; 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_priv); 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->drm; 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_priv: drm_i915_private * @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_i915_private *dev_priv, u32 pin_mask, u32 long_mask) { 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_priv), "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_priv); 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. * * Also see: intel_hpd_poll_init(), which enables connector polling */ void intel_hpd_init(struct drm_i915_private *dev_priv) { int i; for_each_hpd_pin(i) { dev_priv->hotplug.stats[i].count = 0; dev_priv->hotplug.stats[i].state = HPD_ENABLED; } WRITE_ONCE(dev_priv->hotplug.poll_enabled, false); schedule_work(&dev_priv->hotplug.poll_init_work); /* * 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_priv); spin_unlock_irq(&dev_priv->irq_lock); } void i915_hpd_poll_init_work(struct work_struct *work) { struct drm_i915_private *dev_priv = container_of(work, struct drm_i915_private, hotplug.poll_init_work); struct drm_device *dev = &dev_priv->drm; struct drm_mode_config *mode_config = &dev->mode_config; struct drm_connector *connector; bool enabled; mutex_lock(&dev->mode_config.mutex); enabled = READ_ONCE(dev_priv->hotplug.poll_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 = enabled ? DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT : DRM_CONNECTOR_POLL_HPD; } } if (enabled) drm_kms_helper_poll_enable_locked(dev); mutex_unlock(&dev->mode_config.mutex); /* * We might have missed any hotplugs that happened while we were * in the middle of disabling polling */ if (!enabled) drm_helper_hpd_irq_event(dev); } /** * intel_hpd_poll_init - enables/disables polling for connectors with hpd * @dev_priv: i915 device instance * * This function enables polling for all connectors, regardless of whether or * not they support hotplug detection. Under certain conditions HPD may not be * functional. On most Intel GPUs, this happens when we enter runtime suspend. * On Valleyview and Cherryview systems, this also happens when we shut off all * of the powerwells. * * Since this function can get called in contexts where we're already holding * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate * worker. * * Also see: intel_hpd_init(), which restores hpd handling. */ void intel_hpd_poll_init(struct drm_i915_private *dev_priv) { WRITE_ONCE(dev_priv->hotplug.poll_enabled, true); /* * We might already be holding dev->mode_config.mutex, so do this in a * seperate worker * As well, there's no issue if we race here since we always reschedule * this worker anyway */ schedule_work(&dev_priv->hotplug.poll_init_work); } 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_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work); 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_work_sync(&dev_priv->hotplug.poll_init_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); }