On Wed, 25 Aug 2010 21:15:06 +0200, Peter Stuge peter@stuge.se wrote:
In general, Xv performance with KMS leaves me with a feeling that something is not quite right in terms of playback, both with mplayer and vlc. But while movies are nice, this stalling issue is more important.
That should now be fixed in -intel, we allocating a fresh buffer for every frame and incurring massive clflush overhead. However, we have we replaced it with a worse bug...
drm-intel.git as of 07-21 has sortof worked for me, but could not suspend. Later drm-intel.git would come up with the panel disabled, so basically make the system unusable. I've been using 07-21 for about a month, and just avoiding suspending.
I'm now running drm-intel.git/drm-intel-next (which seems to not get the activity first?) and the latest commit is Linus 2.6.36-rc2. I've merged wireless-testing.git on top of this for ath9k woes.
I get the stall precisely every 10 seconds. In VT mode the system stalls for about a second (the cursor stops blinking) and if I'm typing during the stall then my keypresses appear correctly after the stall ends. No errors in dmesg. Should I set drm.debug to something?
This is caused by the hotplug polling code taking around 600ms to determine that the VGA is not connected.
https://bugs.freedesktop.org/show_bug.cgi?id=29536
If I'm running X (I've tried xf86-video-intel 2.12.0 and current .git master) then my keypresses appear twice after the stall ends, but honouring shift. If I hold shift, type X, release shift during a stall then I'll get "Xx" after the stall ends. This makes X practically unusable for me, so I'm at a plain VT for now.
Suspend works both in VT and in X, so some things have definately improved for me since 07-21. :)
I've just upgraded my userspace and have xorg-server-1.8.2. No Xv image with either xf86-video-intel driver. I haven't tried this server with the 07-21 kernel to find out if Xv works there. The stalling is more important.
https://bugs.freedesktop.org/show_bug.cgi?id=29574 (I think, Daniel reported something closer to your issue on IRC, but I don't have an actual bug for that.)
Chris' patch to i915_irq.c disabling wake-ups has no effect on the stalls in VT mode for me.
I haven't bisected, would that be a big help? I'll probably have to spend a fair amount of time on that, since the latest previous kernel I could get to start is over a month old. I've tried drm-intel.git a couple of times over this month, but for long periods of time there were no changes. (Should I look elsewhere?)
No, sounds like you've hit almost all of the recent 855 regressions. But you have a cursor, that is more than most people!
I also get intermittent FIFO errors, but I don't know how relevant they are for this issue. It seems like the stalling is a very distinct issue.
Actually reporting the FIFO issue is new, the problem has been around for a while though. The underlying issue is that we have a very pessimistic guess for the memory fetch and so estimate that we require more FIFO entries than is available on the hardware. The challenge is to build a table of suitable memory latencies that we can use for a more accurate guess, and save power.