On Thu, Feb 28, 2013 at 04:19:15AM -0500, Egbert Eich wrote:
> Add a hotplug IRQ storm detection (triggered when a hotplug interrupt
> fires more than 5 times / sec).
> Rationale:
> Despite of the many attempts to fix the problem with noisy hotplug
> interrupt lines we are still seeing systems which have issues:
> Once cause of noise seems to be bad routing of the hotplug line
> on the board: cross talk from other signals seems to cause erronous
> hotplug interrupts. This has been documented as an erratum for the
> the i945GM chipset and thus hotplug support was disabled for this
> chipset model but others seem to have this problem, too.
>
> We have seen this issue on a G35 motherboard for example:
> Even different motherboards of the same model seem to behave
> differently: while some only see only around 10-100 interrupts/s
> others seem to see 5k or more.
> We've also observed a dependency on the selected video mode.
>
> Also on certain laptops interrupt noise seems to occur duing
> battery charging when the battery is at a certain charge levels.
>
> Thus we add a simple algorithm here that detects an 'interrupt storm'
> condition.
>
> v2: Fixed comment.
>
> Signed-off-by: Egbert Eich <eich at suse.de>
> Acked-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 9 +++++
> drivers/gpu/drm/i915/i915_irq.c | 63 +++++++++++++++++++++++++++++++-------
> 2 files changed, 60 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index d8604a6..6ca742d 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1059,6 +1059,15 @@ typedef struct drm_i915_private {
> /* Old dri1 support infrastructure, beware the dragons ya fools entering
> * here! */
> struct i915_dri1_state dri1;
> + struct {
> + unsigned long hpd_last_jiffies;
> + int hpd_cnt;
> + enum {
> + HPD_ENABLED = 0,
> + HPD_DISABLED = 1,
> + HPD_MARK_DISABLED = 2
> + } hpd_mark;
> + } hpd_stats[HPD_NUM_PINS];
It's still hidden in the dri1 dungeon ;-) Imo this would fit nicely next
to the existing hotplug work and state tracking stuff.
-Daniel
> } drm_i915_private_t;
>
> /* Iterate over initialised rings */
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index c40c7cc..24cb6ed 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -578,6 +578,34 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
> queue_work(dev_priv->wq, &dev_priv->rps.work);
> }
>
> +static inline void 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;
> +
> + spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +
> + for (i = 1; i < HPD_NUM_PINS; i++) {
> + if ((hpd[i] & hotplug_trigger) &&
> + dev_priv->hpd_stats[i].hpd_mark == HPD_ENABLED) {
> + if (jiffies > (dev_priv->hpd_stats[i].hpd_last_jiffies + msecs_to_jiffies(1000)) ||
> + jiffies < dev_priv->hpd_stats[i].hpd_last_jiffies) {
> + dev_priv->hpd_stats[i].hpd_last_jiffies = jiffies;
> + dev_priv->hpd_stats[i].hpd_cnt = 0;
> + } else if (dev_priv->hpd_stats[i].hpd_cnt > 5) {
> + dev_priv->hpd_stats[i].hpd_mark = HPD_MARK_DISABLED;
> + DRM_DEBUG_KMS("HPD interrupt storm detected on PIN %d\n", i);
> + } else
> + dev_priv->hpd_stats[i].hpd_cnt++;
> + }
> + }
> +
> + spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}
> +
> static void gmbus_irq_handler(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = (drm_i915_private_t *) dev->dev_private;
> @@ -646,13 +674,15 @@ static irqreturn_t valleyview_irq_handler(int irq, void *arg)
> /* Consume port. Then clear IIR or we'll miss events */
> if (iir & I915_DISPLAY_PORT_INTERRUPT) {
> u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
> + u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
>
> DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
> hotplug_status);
> - if (hotplug_status & HOTPLUG_INT_STATUS_I915)
> + if (hotplug_trigger) {
> + hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
> queue_work(dev_priv->wq,
> &dev_priv->hotplug_work);
> -
> + }
> I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
> I915_READ(PORT_HOTPLUG_STAT);
> }
> @@ -676,10 +706,12 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
> {
> drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
> int pipe;
> + u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK;
>
> - if (pch_iir & SDE_HOTPLUG_MASK)
> + if (hotplug_trigger) {
> + hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_ibx);
> queue_work(dev_priv->wq, &dev_priv->hotplug_work);
> -
> + }
> if (pch_iir & SDE_AUDIO_POWER_MASK)
> DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
> (pch_iir & SDE_AUDIO_POWER_MASK) >>
> @@ -722,10 +754,12 @@ static void cpt_irq_handler(struct drm_device *dev, u32 pch_iir)
> {
> drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
> int pipe;
> + u32 hotplug_trigger = pch_iir & SDE_HOTPLUG_MASK_CPT;
>
> - if (pch_iir & SDE_HOTPLUG_MASK_CPT)
> + if (hotplug_trigger) {
> + hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_cpt);
> queue_work(dev_priv->wq, &dev_priv->hotplug_work);
> -
> + }
> if (pch_iir & SDE_AUDIO_POWER_MASK_CPT)
> DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
> (pch_iir & SDE_AUDIO_POWER_MASK_CPT) >>
> @@ -2468,13 +2502,15 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
> if ((I915_HAS_HOTPLUG(dev)) &&
> (iir & I915_DISPLAY_PORT_INTERRUPT)) {
> u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
> + u32 hotplug_trigger = hotplug_status & HOTPLUG_INT_STATUS_I915;
>
> DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
> hotplug_status);
> - if (hotplug_status & HOTPLUG_INT_STATUS_I915)
> + if (hotplug_trigger) {
> + hotplug_irq_storm_detect(dev, hotplug_trigger, hpd_status_i915);
> queue_work(dev_priv->wq,
> &dev_priv->hotplug_work);
> -
> + }
> I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
> POSTING_READ(PORT_HOTPLUG_STAT);
> }
> @@ -2701,15 +2737,18 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
> /* Consume port. Then clear IIR or we'll miss events */
> if (iir & I915_DISPLAY_PORT_INTERRUPT) {
> u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
> + u32 hotplug_trigger = hotplug_status & (IS_G4X(dev) ?
> + HOTPLUG_INT_STATUS_G4X :
> + HOTPLUG_INT_STATUS_I965);
>
> DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
> hotplug_status);
> - if (hotplug_status & (IS_G4X(dev) ?
> - HOTPLUG_INT_STATUS_G4X :
> - HOTPLUG_INT_STATUS_I965))
> + if (hotplug_trigger) {
> + hotplug_irq_storm_detect(dev, hotplug_trigger,
> + IS_G4X(dev) ? hpd_status_gen4 : hpd_status_i965);
> queue_work(dev_priv->wq,
> &dev_priv->hotplug_work);
> -
> + }
> I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
> I915_READ(PORT_HOTPLUG_STAT);
> }
> --
> 1.7.7
>
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
