Hello,

We have been attempting to debug an issue that we have been having for a few weeks related to audio playback. Specifically, over time, the playback of audio gets 'stuck' for a while (60 seconds or so), then quickly advances forward again (for about 60 seconds), then gets stuck again. It continues to repeat this until I either stop playback or pause/play. We have dubbed it 'skip-lock' as it skips ahead, then locks for a bit. It takes a while to reproduce this behavior, typically around 6 hours.

We have about 30 of these systems setup, each with the same hardware configuration. They have a VIA C7 CPU (1.5GHz), 1GB RAM, and they are using the VIA 8233A AC97 controller with an ALC655 codec. The system is SATA based (using sata_via), and an RTL8110 gigabit ethernet controller (using rtl8169).

For the OS, we are using Debian Etch with the 2.6.29 kernel, and we have tested a number of these units with 2.6.24-etchnhalf as well. ALSA lib 1.0.13 (from the install) is still in use, but I am trying out 1.0.19 on a few of the units to see if it helps. The player we use is called BlueTune, which we have used in older systems for years without trouble. I plan on trying to set up another player app to do the same testing, but haven't had the time to do that yet. On most of the systems, the player is using the default alsa output. I have configured a few systems to use plughw:0,0,0 for playback (mainly so that /dev/snd/timer is not used), and they have not had any playback issues so far (about 24 hours so far).

After a bunch of other tests, we started to run strace against the player. We saw that it was repeatedly getting EAGAIN when reading from /dev/snd/timer during the 'stuck' phase. I have started to poke around a bit more in the timer code and see why EAGAIN is repeatedly being generated (in snd_timer_user_read, tu->qused is stuck at 0 for a while). I figured that if anybody had some things to try or places to look, it might save a bit of time in finding the cause of this issue.

Thanks! Ron

PS: I apologize if this is the wrong place to post this. I had posted a not-terribly-detailed message to alsa-user a few weeks ago, but have gained more data that I felt fit better here.