Subject: [linux-audio-dev] 2.4.20-rc1 + lowlat + preempt + alsa + jack = dead computer
From: Fernando Pablo Lopez-Lezcano (nando_AT_ccrma.Stanford.EDU)
Date: Sat Nov 02 2002 - 02:00:57 EET
[sorry for the wide distribution]
Is anyone out there trying out this combination?:
kernel 2.4.20-rc1
capabilities patch
low latency patch
preemptible kernel patch
almost current alsa cvs [20021028.170432 usa pacific time]
If I start jackd and then use the freqtweak jack client I get a completely
dead machine in a very short time (from a few seconds to 10 or 20
seconds).
Same alsa driver, but running on 2.4.19 (up to 20-pre4) seems to be fine
and I can play around with freqtweak for as long as I want :-)
No clues are left behind... something in the kernel is deadlocking, I
guess. I tried removing first the preemptible kernel patch with the same
result. Just a moment ago I tried again after removing the low latency
patch and I still get the same result... that pretty much leaves alsa and
the kernel. Got the same result on a laptop intel810 and an ice1712 card.
Interestingly enough just the jack server running is not enough to kill
the machine. Adding a jack client (just tried alsaplayer, same problem as
freqtweak) kills the machine really fast.
Maybe there is a problem with the scheduler when there are several
SCHED_FIFO tasks competing for the processor?
-- Fernando
This archive was generated by hypermail 2b28 : Sat Nov 02 2002 - 02:32:26 EET