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path: root/drivers/gpu/drm/i915/display/intel_hotplug.c
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Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_hotplug.c')
-rw-r--r--drivers/gpu/drm/i915/display/intel_hotplug.c687
1 files changed, 687 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
new file mode 100644
index 000000000000..ea3de4acc850
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
@@ -0,0 +1,687 @@
+/*
+ * 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/i915_drm.h>
+
+#include "i915_drv.h"
+#include "intel_drv.h"
+#include "intel_hotplug.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.
+ */
+
+/**
+ * intel_hpd_pin_default - return default pin associated with certain port.
+ * @dev_priv: private driver data pointer
+ * @port: the hpd port to get associated pin
+ *
+ * It is only valid and used by digital port encoder.
+ *
+ * Return pin that is associatade with @port and HDP_NONE if no pin is
+ * hard associated with that @port.
+ */
+enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv,
+ enum port port)
+{
+ switch (port) {
+ case PORT_A:
+ return HPD_PORT_A;
+ case PORT_B:
+ return HPD_PORT_B;
+ case PORT_C:
+ return HPD_PORT_C;
+ case PORT_D:
+ return HPD_PORT_D;
+ case PORT_E:
+ return HPD_PORT_E;
+ case PORT_F:
+ if (IS_CNL_WITH_PORT_F(dev_priv))
+ return HPD_PORT_E;
+ return HPD_PORT_F;
+ default:
+ MISSING_CASE(port);
+ return HPD_NONE;
+ }
+}
+
+#define HPD_STORM_DETECT_PERIOD 1000
+#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
+ * @long_hpd: whether the HPD IRQ was long or short
+ *
+ * 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.
+ *
+ * The number of IRQs that are allowed within @HPD_STORM_DETECT_PERIOD is
+ * stored in @dev_priv->hotplug.hpd_storm_threshold which defaults to
+ * @HPD_STORM_DEFAULT_THRESHOLD. Long IRQs count as +10 to this threshold, and
+ * short IRQs count as +1. If this threshold is exceeded, it's considered an
+ * IRQ storm and the IRQ state is set to @HPD_MARK_DISABLED.
+ *
+ * By default, most systems will only count long IRQs towards
+ * &dev_priv->hotplug.hpd_storm_threshold. However, some older systems also
+ * suffer from short IRQ storms and must also track these. Because short IRQ
+ * storms are naturally caused by sideband interactions with DP MST devices,
+ * short IRQ detection is only enabled for systems without DP MST support.
+ * Systems which are new enough to support DP MST are far less likely to
+ * suffer from IRQ storms at all, so this is fine.
+ *
+ * The HPD threshold can be controlled through i915_hpd_storm_ctl in debugfs,
+ * and should only be adjusted for automated hotplug testing.
+ *
+ * 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, bool long_hpd)
+{
+ struct i915_hotplug *hpd = &dev_priv->hotplug;
+ unsigned long start = hpd->stats[pin].last_jiffies;
+ unsigned long end = start + msecs_to_jiffies(HPD_STORM_DETECT_PERIOD);
+ const int increment = long_hpd ? 10 : 1;
+ const int threshold = hpd->hpd_storm_threshold;
+ bool storm = false;
+
+ if (!threshold ||
+ (!long_hpd && !dev_priv->hotplug.hpd_short_storm_enabled))
+ return false;
+
+ if (!time_in_range(jiffies, start, end)) {
+ hpd->stats[pin].last_jiffies = jiffies;
+ hpd->stats[pin].count = 0;
+ }
+
+ hpd->stats[pin].count += increment;
+ if (hpd->stats[pin].count > threshold) {
+ hpd->stats[pin].state = HPD_MARK_DISABLED;
+ DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", pin);
+ storm = true;
+ } else {
+ DRM_DEBUG_KMS("Received HPD interrupt on PIN %d - cnt: %d\n", pin,
+ hpd->stats[pin].count);
+ }
+
+ return storm;
+}
+
+static void
+intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
+{
+ struct drm_device *dev = &dev_priv->drm;
+ struct intel_connector *intel_connector;
+ struct intel_encoder *intel_encoder;
+ struct drm_connector *connector;
+ struct drm_connector_list_iter conn_iter;
+ enum hpd_pin pin;
+ bool hpd_disabled = false;
+
+ lockdep_assert_held(&dev_priv->irq_lock);
+
+ drm_connector_list_iter_begin(dev, &conn_iter);
+ drm_for_each_connector_iter(connector, &conn_iter) {
+ 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;
+ }
+ drm_connector_list_iter_end(&conn_iter);
+
+ /* 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->drm;
+ intel_wakeref_t wakeref;
+ enum hpd_pin pin;
+
+ wakeref = intel_runtime_pm_get(&dev_priv->runtime_pm);
+
+ spin_lock_irq(&dev_priv->irq_lock);
+ for_each_hpd_pin(pin) {
+ struct drm_connector *connector;
+ struct drm_connector_list_iter conn_iter;
+
+ if (dev_priv->hotplug.stats[pin].state != HPD_DISABLED)
+ continue;
+
+ dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
+
+ drm_connector_list_iter_begin(dev, &conn_iter);
+ drm_for_each_connector_iter(connector, &conn_iter) {
+ struct intel_connector *intel_connector = to_intel_connector(connector);
+
+ /* Don't check MST ports, they don't have pins */
+ if (!intel_connector->mst_port &&
+ intel_connector->encoder->hpd_pin == pin) {
+ 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;
+ }
+ }
+ drm_connector_list_iter_end(&conn_iter);
+ }
+ if (dev_priv->display_irqs_enabled && 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->runtime_pm, wakeref);
+}
+
+bool intel_encoder_hotplug(struct intel_encoder *encoder,
+ struct intel_connector *connector)
+{
+ struct drm_device *dev = connector->base.dev;
+ enum drm_connector_status old_status;
+
+ WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
+ old_status = connector->base.status;
+
+ connector->base.status =
+ drm_helper_probe_detect(&connector->base, NULL, false);
+
+ if (old_status == connector->base.status)
+ return false;
+
+ DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
+ connector->base.base.id,
+ connector->base.name,
+ drm_get_connector_status_name(old_status),
+ drm_get_connector_status_name(connector->base.status));
+
+ return true;
+}
+
+static bool intel_encoder_has_hpd_pulse(struct intel_encoder *encoder)
+{
+ return intel_encoder_is_dig_port(encoder) &&
+ enc_to_dig_port(&encoder->base)->hpd_pulse != NULL;
+}
+
+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_encoder *encoder;
+ 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_each_intel_encoder(&dev_priv->drm, encoder) {
+ struct intel_digital_port *dig_port;
+ enum port port = encoder->port;
+ bool long_hpd, short_hpd;
+ enum irqreturn ret;
+
+ if (!intel_encoder_has_hpd_pulse(encoder))
+ continue;
+
+ long_hpd = long_port_mask & BIT(port);
+ short_hpd = short_port_mask & BIT(port);
+
+ if (!long_hpd && !short_hpd)
+ continue;
+
+ dig_port = enc_to_dig_port(&encoder->base);
+
+ ret = dig_port->hpd_pulse(dig_port, long_hpd);
+ if (ret == IRQ_NONE) {
+ /* fall back to old school hpd */
+ old_bits |= BIT(encoder->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 intel_connector *intel_connector;
+ struct intel_encoder *intel_encoder;
+ struct drm_connector *connector;
+ struct drm_connector_list_iter conn_iter;
+ bool changed = false;
+ u32 hpd_event_bits;
+
+ mutex_lock(&dev->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;
+
+ /* Enable polling for connectors which had HPD IRQ storms */
+ intel_hpd_irq_storm_switch_to_polling(dev_priv);
+
+ spin_unlock_irq(&dev_priv->irq_lock);
+
+ drm_connector_list_iter_begin(dev, &conn_iter);
+ drm_for_each_connector_iter(connector, &conn_iter) {
+ 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);
+
+ changed |= intel_encoder->hotplug(intel_encoder,
+ intel_connector);
+ }
+ }
+ drm_connector_list_iter_end(&conn_iter);
+ mutex_unlock(&dev->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)
+{
+ struct intel_encoder *encoder;
+ bool storm_detected = false;
+ bool queue_dig = false, queue_hp = false;
+ u32 long_hpd_pulse_mask = 0;
+ u32 short_hpd_pulse_mask = 0;
+ enum hpd_pin pin;
+
+ if (!pin_mask)
+ return;
+
+ spin_lock(&dev_priv->irq_lock);
+
+ /*
+ * Determine whether ->hpd_pulse() exists for each pin, and
+ * whether we have a short or a long pulse. This is needed
+ * as each pin may have up to two encoders (HDMI and DP) and
+ * only the one of them (DP) will have ->hpd_pulse().
+ */
+ for_each_intel_encoder(&dev_priv->drm, encoder) {
+ bool has_hpd_pulse = intel_encoder_has_hpd_pulse(encoder);
+ enum port port = encoder->port;
+ bool long_hpd;
+
+ pin = encoder->hpd_pin;
+ if (!(BIT(pin) & pin_mask))
+ continue;
+
+ if (!has_hpd_pulse)
+ continue;
+
+ long_hpd = long_mask & BIT(pin);
+
+ DRM_DEBUG_DRIVER("digital hpd port %c - %s\n", port_name(port),
+ long_hpd ? "long" : "short");
+ queue_dig = true;
+
+ if (long_hpd) {
+ long_hpd_pulse_mask |= BIT(pin);
+ dev_priv->hotplug.long_port_mask |= BIT(port);
+ } else {
+ short_hpd_pulse_mask |= BIT(pin);
+ dev_priv->hotplug.short_port_mask |= BIT(port);
+ }
+ }
+
+ /* Now process each pin just once */
+ for_each_hpd_pin(pin) {
+ bool long_hpd;
+
+ if (!(BIT(pin) & pin_mask))
+ continue;
+
+ if (dev_priv->hotplug.stats[pin].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(dev_priv),
+ "Received HPD interrupt on pin %d although disabled\n", pin);
+ continue;
+ }
+
+ if (dev_priv->hotplug.stats[pin].state != HPD_ENABLED)
+ continue;
+
+ /*
+ * Delegate to ->hpd_pulse() if one of the encoders for this
+ * pin has it, otherwise let the hotplug_work deal with this
+ * pin directly.
+ */
+ if (((short_hpd_pulse_mask | long_hpd_pulse_mask) & BIT(pin))) {
+ long_hpd = long_hpd_pulse_mask & BIT(pin);
+ } else {
+ dev_priv->hotplug.event_bits |= BIT(pin);
+ long_hpd = true;
+ queue_hp = true;
+ }
+
+ if (intel_hpd_irq_storm_detect(dev_priv, pin, long_hpd)) {
+ dev_priv->hotplug.event_bits &= ~BIT(pin);
+ storm_detected = true;
+ queue_hp = true;
+ }
+ }
+
+ /*
+ * Disable any IRQs that storms were detected on. Polling enablement
+ * happens later in our hotplug work.
+ */
+ if (storm_detected && dev_priv->display_irqs_enabled)
+ 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.
+ */
+ if (dev_priv->display_irqs_enabled && dev_priv->display.hpd_irq_setup) {
+ spin_lock_irq(&dev_priv->irq_lock);
+ if (dev_priv->display_irqs_enabled)
+ dev_priv->display.hpd_irq_setup(dev_priv);
+ spin_unlock_irq(&dev_priv->irq_lock);
+ }
+}
+
+static 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_connector *connector;
+ struct drm_connector_list_iter conn_iter;
+ bool enabled;
+
+ mutex_lock(&dev->mode_config.mutex);
+
+ enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);
+
+ drm_connector_list_iter_begin(dev, &conn_iter);
+ drm_for_each_connector_iter(connector, &conn_iter) {
+ 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_priv) &&
+ intel_connector->encoder->hpd_pin > HPD_NONE) {
+ connector->polled = enabled ?
+ DRM_CONNECTOR_POLL_CONNECT |
+ DRM_CONNECTOR_POLL_DISCONNECT :
+ DRM_CONNECTOR_POLL_HPD;
+ }
+ }
+ drm_connector_list_iter_end(&conn_iter);
+
+ if (enabled)
+ drm_kms_helper_poll_enable(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);
+}