Hi list,
I was busy, but this is important so I report my findings:
Am 08.07.2013 22:03, schrieb Daniel Vetter:
On Sat, Jul 06, 2013 at 11:41:07PM +0200, Jan Niggemann wrote:
Hi list,
I'm not sure, but I think the recent patch to keep i915 systems from
locking up / slowing down in case of irq storms didn't fully help.
I compiled 3.10, but every now and then, my system has the same
symptoms as before.
grep storm /var/log/messages
Jul 5 21:55:43 muretop kernel: [ 324.767375] [drm] HPD interrupt
storm detected on connector DP-3: switching from hotplug detection
to polling
Jul 6 23:05:57 muretop kernel: [ 200.372208] [drm] HPD interrupt
storm detected on connector HDMI-A-1: switching from hotplug
detection to polling
Jul 6 23:07:51 muretop kernel: [ 313.752039] [drm] HPD interrupt
storm detected on connector DP-3: switching from hotplug detection
to pol
I notice up to 50% CPU from kworker/u8:0 when my system slows down.
I'm new to kernel development, but if you tell me what to do, I'm
very willing to help diagnosing this.
Seems to work as advertised, once we detect a storm we kill the
hotplug
interrupt. Note that since on many systems these storms only happen
in
certain conditions (e.g. specific battery charger state) we'll
re-enable
the interrupts every 2 minutes to check whether the storm has passed
(there's not really any other way).
OK, I didn't know it worked that way.
But every time this happens we only let through a few interrupts, so
this
shouldn't affect you badly. Can you please check whether those
slowdowns
line up with 2 minute intervalls?
I observed these slowdowns for a couple of weeks now. On my machine,
they only happen once, some minutes after a cold boot.
They last for a minute or two, and then they are gone.
I'd have guessed that the storm detection kicks in pretty quickly after
a storm is detected and that it would go unnoticed.
Another thing I have noticed: All storm-related messages are about DP-3
and HDMI-A-1, but my T400 doesn't have either a HDMI out nor a
DisplayPort connector...
I returned to 3.2.0 with drm_kms_helper.poll=0 for the time being, so
this doesn't affect me badly.
Please tell me if and how I can further diagnose this.
Jan
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