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drm/i915: Don't WARN nor handle unexpected hpd interrupts on gmch platforms 

The status bits are unconditionally set, the control bits only enable
the actual interrupt generation. Which means if we get some random
other interrupts we'll bogusly complain about them.

So restrict the WARN to platforms with a sane hotplug interrupt
handling scheme. And even more important also don't attempt to process
the hpd bit since we've detected a storm already. Instead just clear
the bit silently.

This WARN has been introduced in

commit b8f102e8bf
Author: Egbert Eich <eich@suse.de>
Date:   Fri Jul 26 14:14:24 2013 +0200

    drm/i915: Add messages useful for HPD storm detection debugging (v2)

before that we silently handled the hpd event and so partially
defeated the storm detection.

v2: Pimp commit message (Jani)

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Egbert Eich <eich@suse.de>
Cc: bitlord <bitlord0xff@gmail.com>
Reported-by: bitlord <bitlord0xff@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Daniel Vetter 2014-04-24 12:03:17 +02:00 committed by Jani Nikula
parent 0f9dc59db6
commit 3ff04a160a
1 changed files with 14 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/gpu/drm/i915/i915_irq.c
View File

@ -1362,11 +1362,21 @@ static inline void intel_hpd_irq_handler(struct drm_device *dev,
spin_lock(&dev_priv->irq_lock);
for (i = 1; i < HPD_NUM_PINS; i++) {
WARN_ONCE(hpd[i] & hotplug_trigger &&
dev_priv->hpd_stats[i].hpd_mark == HPD_DISABLED,
if (hpd[i] & hotplug_trigger &&
dev_priv->hpd_stats[i].hpd_mark == 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 (0x%08x) on pin %d (0x%08x) although disabled\n",
hotplug_trigger, i, hpd[i]);
continue;
}
if (!(hpd[i] & hotplug_trigger) ||
dev_priv->hpd_stats[i].hpd_mark != HPD_ENABLED)
continue;