diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_hotplug.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_hotplug.c | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c new file mode 100644 index 000000000000..53c0173a39fe --- /dev/null +++ b/drivers/gpu/drm/i915/intel_hotplug.c @@ -0,0 +1,508 @@ +/* + * 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 <linux/kernel.h> + +#include <drm/drmP.h> +#include <drm/i915_drm.h> + +#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(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(INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(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; + if (connector->encoder && !connector->polled && I915_HAS_HOTPLUG(dev) && intel_connector->encoder->hpd_pin > HPD_NONE) + connector->polled = DRM_CONNECTOR_POLL_HPD; + if (intel_connector->mst_port) + 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); +} |