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drm/i915: Disable HPD interrupt on pin when irq storm is detected (v3)
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This patch disables hotplug interrupts if an 'interrupt storm'
has been detected.
Noise on the interrupt line renders the hotplug interrupt useless:
each hotplug event causes the devices to be rescanned which will
will only increase the system load.
Thus disable the hotplug interrupts and fall back to periodic
device polling.

v2: Fixed cleanup typo.
v3: Fixed format issues, clarified a variable name,
    changed pr_warn() to DRM_INFO() as suggested by
    Jani Nikula <jani.nikula@linux.intel.com>.

Signed-off-by: Egbert Eich <eich@suse.de>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Egbert Eich authored and Daniel Vetter committed Apr 18, 2013
1 parent 995e6b3 commit cd569ae
Showing 1 changed file with 58 additions and 17 deletions.
75 changes: 58 additions & 17 deletions drivers/gpu/drm/i915/i915_irq.c
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Original file line number Diff line number Diff line change
Expand Up @@ -88,7 +88,8 @@ static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
[HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
};


static void ibx_hpd_irq_setup(struct drm_device *dev);
static void i915_hpd_irq_setup(struct drm_device *dev);

/* For display hotplug interrupt */
static void
Expand Down Expand Up @@ -342,7 +343,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
hotplug_work);
struct drm_device *dev = dev_priv->dev;
struct drm_mode_config *mode_config = &dev->mode_config;
struct intel_encoder *encoder;
struct intel_connector *intel_connector;
struct intel_encoder *intel_encoder;
struct drm_connector *connector;
unsigned long irqflags;
bool hpd_disabled = false;

/* HPD irq before everything is fully set up. */
if (!dev_priv->enable_hotplug_processing)
Expand All @@ -351,9 +356,33 @@ static void i915_hotplug_work_func(struct work_struct *work)
mutex_lock(&mode_config->mutex);
DRM_DEBUG_KMS("running encoder hotplug functions\n");

list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
if (encoder->hot_plug)
encoder->hot_plug(encoder);
spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
list_for_each_entry(connector, &mode_config->connector_list, head) {
intel_connector = to_intel_connector(connector);
intel_encoder = intel_connector->encoder;
if (intel_encoder->hpd_pin > HPD_NONE &&
dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_MARK_DISABLED &&
connector->polled == DRM_CONNECTOR_POLL_HPD) {
DRM_INFO("HPD interrupt storm detected on connector %s: "
"switching from hotplug detection to polling\n",
drm_get_connector_name(connector));
dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark = HPD_DISABLED;
connector->polled = DRM_CONNECTOR_POLL_CONNECT
| DRM_CONNECTOR_POLL_DISCONNECT;
hpd_disabled = true;
}
}
/* if there were no outputs to poll, poll was disabled,
* therefore make sure it's enabled when disabling HPD on
* some connectors */
if (hpd_disabled)
drm_kms_helper_poll_enable(dev);

spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
if (intel_encoder->hot_plug)
intel_encoder->hot_plug(intel_encoder);

mutex_unlock(&mode_config->mutex);

Expand Down Expand Up @@ -585,13 +614,14 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
#define HPD_STORM_DETECT_PERIOD 1000
#define HPD_STORM_THRESHOLD 5

static inline void hotplug_irq_storm_detect(struct drm_device *dev,
static inline bool hotplug_irq_storm_detect(struct drm_device *dev,
u32 hotplug_trigger,
const u32 *hpd)
{
drm_i915_private_t *dev_priv = dev->dev_private;
unsigned long irqflags;
int i;
bool ret = false;

spin_lock_irqsave(&dev_priv->irq_lock, irqflags);

Expand All @@ -609,12 +639,15 @@ static inline void hotplug_irq_storm_detect(struct drm_device *dev,
} else if (dev_priv->hpd_stats[i].hpd_cnt > HPD_STORM_THRESHOLD) {
dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", i);
ret = true;
} else {
dev_priv->hpd_stats[i].hpd_cnt++;
}
}

spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);

return ret;
}

static void gmbus_irq_handler(struct drm_device *dev)
Expand Down Expand Up @@ -690,7 +723,8 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
hotplug_status);
if (hotplug_trigger) {
hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915))
i915_hpd_irq_setup(dev);
queue_work(dev_priv->wq,
&dev_priv->hotplug_work);
}
Expand Down Expand Up @@ -720,7 +754,8 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;

if (hotplug_trigger) {
hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx);
if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx))
ibx_hpd_irq_setup(dev);
queue_work(dev_priv->wq, &dev_priv->hotplug_work);
}
if (pch_iir & SDE_AUDIO_POWER_MASK)
Expand Down Expand Up @@ -768,7 +803,8 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;

if (hotplug_trigger) {
hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt);
if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt))
ibx_hpd_irq_setup(dev);
queue_work(dev_priv->wq, &dev_priv->hotplug_work);
}
if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
Expand Down Expand Up @@ -2130,11 +2166,13 @@ static void ibx_hpd_irq_setup(struct drm_device *dev)
if (HAS_PCH_IBX(dev)) {
mask &= ~SDE_HOTPLUG_MASK;
list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
mask |= hpd_ibx[intel_encoder->hpd_pin];
if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
mask |= hpd_ibx[intel_encoder->hpd_pin];
} else {
mask &= ~SDE_HOTPLUG_MASK_CPT;
list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
mask |= hpd_cpt[intel_encoder->hpd_pin];
if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
mask |= hpd_cpt[intel_encoder->hpd_pin];
}

I915_WRITE(SDEIMR, ~mask);
Expand Down Expand Up @@ -2669,7 +2707,8 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
hotplug_status);
if (hotplug_trigger) {
hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
if (hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915))
i915_hpd_irq_setup(dev);
queue_work(dev_priv->wq,
&dev_priv->hotplug_work);
}
Expand Down Expand Up @@ -2819,16 +2858,17 @@ static void i915_hpd_irq_setup(struct drm_device *dev)
{
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
struct drm_mode_config *mode_config = &dev->mode_config;
struct intel_encoder *encoder;
struct intel_encoder *intel_encoder;
u32 hotplug_en;

if (I915_HAS_HOTPLUG(dev)) {
hotplug_en = I915_READ(PORT_HOTPLUG_EN);
hotplug_en &= ~HOTPLUG_INT_EN_MASK;
/* Note HDMI and DP share hotplug bits */
/* enable bits are the same for all generations */
list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
hotplug_en |= hpd_mask_i915[encoder->hpd_pin];
list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
if (dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_ENABLED)
hotplug_en |= hpd_mask_i915[intel_encoder->hpd_pin];
/* Programming the CRT detection parameters tends
to generate a spurious hotplug event about three
seconds later. So just do it once.
Expand Down Expand Up @@ -2906,8 +2946,9 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
hotplug_status);
if (hotplug_trigger) {
hotplug_irq_storm_detect(dev, hotplug_trigger,
IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965);
if (hotplug_irq_storm_detect(dev, hotplug_trigger,
IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965))
i915_hpd_irq_setup(dev);
queue_work(dev_priv->wq,
&dev_priv->hotplug_work);
}
Expand Down

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