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Date: Sat, 5 Jun 2004 15:08:17 +0800 (CST)
From: Tai-hwa Liang <avatar@mmlab.cse.yzu.edu.tw>
To: Don Lewis <truckman@FreeBSD.org>
In-Reply-To: <200406050514.i555EPJM004758@gw.catspoiler.org>
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cc: freebsd-current@FreeBSD.org
cc: dl@leo.org
Subject: Re: LOR No 9 and strange other kernel messages
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On Fri, 4 Jun 2004, Don Lewis wrote:
> On  4 Jun, Tai-hwa Liang wrote:
> > On Fri, 4 Jun 2004, Daniel Lang wrote:
> >> Hi,
> >>
> >> I just went through my syslog and stumbled across a LOR, which is
> >> documented on the Zabbadoz LOR page (id 009).
> >>
> >> The reason for this mail is the following kernel messages:
> >>
> >> [..]
> >> Jun  1 11:08:06 atrbg11 kernel: x: 2
> >> Jun  1 11:08:06 atrbg11 kernel: x: 2
> >> [..]
> >>
> >> Seems some leftovers from a developer who did not want to
> >> bother others with the gory details. ;-))
> >
> > I guess that came from sys/dev/sound/pcm/sound.c:872. My Thinkpad T40 also
> > ran into this when the disk/network(combination) load is high enough.
>
> Looks likely, but I'd expect this would only get triggered when sysctl
> is used to set or query the number of vchans.  In any case, this marks
> another spot where locking is broken in the sound code.

I use the default setting without tweaking any vchan related sysctl
such like hw.snd.pcm0.vchans(leave it to default 0) or hw.snd.maxautovchans
(also left to 0 on my T40).

I'm wondering about whether this "bug" is ACPI related(interrupt storm?)
since recently when I run "make buildworld buildkernel" on one terminal and
do large file transmission(FTP ISO images on using em0) at the same time,
the sound tends to become "broken." Meanwhile, the "x: 2" message popped
on my console and later on my em0 doesn't work anymore(I have to do a reboot
to get it back; however, the other part of the system still works while
em0 was dead: sound continue playing, can compile/edit programs).