/*
* 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);
}
