PCM2702 (alien dac) with Ubuntu / Alsa intermittent problem

[zog666]

Hi,

I have constructed an Alien DAC a few weeks ago, and it sounds great! We have been using it a lot for the main loungeroom system, using Ubuntu as the playback system, listening to music (rhythmbox, audacious), watching moves (mplayer) and youtube (flashplayer).

One minor issue we have hit is that infrequently - perhaps once a week - only while using flashplayer, the output of the Alien DAC will change to white noise. Shutting down flashplayer will reset the audio connection and the problem goes away, still the blast of white noise through the main system is annoying and sometimes very loud.

This has never happened with any other software besides flashplayer, which points to a software only issue. As there is about a 7 day turn around to reproduce the problem it's going to take me a while to cycle through various driver, kernel and software options until I solve this problem so I'm just seeing if anybody else has seen the same thing or has a solution.
Asking here first as elsewhere the usage of the PCM2702 chip is not so common!

Some tech details:

aplay -l
**** List of PLAYBACK Hardware Devices ****
card 1: PCM2702 [Burr-Brown Japan PCM2702], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0

uname -a
Linux scion 2.6.24-24-generic #1 SMP Tue Jun 30 20:28:53 UTC 2009 i686 GNU/Linux

Operating system is Xubuntu Hardy Heron.
Machine is a 2.8Ghz P4 with 512MB of RAM
On board sound card is disabled.
The machine previously was used with a Behringer UCA-202 and a noname USB sound card from Dick Smith Electronics in the same way with no issues.
My wife uses this PC to watch a LOT of youtube! So it could take dozens of hours of flashplayer to trigger the problem. Unlike using an mp3player I have yet to rig up a continuous youtube player to force the problem to occur more rapidly.

I have been able to get some of the /proc/asound output, the only substantial difference I can see is when using flashplayer:
================================================== ==
/proc/asound/card1/stream0
::::::::::::::
Burr-Brown Japan Burr-Brown Japan PCM2702 at usb-0000:00:1f.2-2, full speed : USB Audio

Playback:
Status: Running
Interface = 1
Altset = 1
URBs = 3 [ 8 8 5 ]
Packet Size = 192
Momentary freq = 44100 Hz (0x2c.199a)
================================================== ===
when using audacious:
================================================== ===
/proc/asound/card1/stream0
::::::::::::::
Burr-Brown Japan Burr-Brown Japan PCM2702 at usb-0000:00:1f.2-2, full speed : USB Audio

Playback:
Status: Running
Interface = 1
Altset = 1
URBs = 8 [ 8 8 8 8 8 8 8 8 ]
Packet Size = 192
Momentary freq = 44100 Hz (0x2c.199a)
================================================== ====

Though from my reading these "URBS" are set via device options at device load time rather than playback? but google is fairly sparse on the details of their signifigance, or how to change them at runtime.

Some ideas I have had that might help are: kernel upgrade - trying different "nrpacks" command line for usb audio - perhaps trying to use flashplayer via jackd or pulseaudio or some other "shim" audio device while still allowing the music players direct access for best layback quality.

ok braindump completed, thanks.

[zog666]

well, next phase of problem solving entered, 2.6.30 kernel installed (including requisite messing about with nvidia legacy drivers and what not). Now for a few weeks of listening to see if the problem repeats.

[zog666]

well a follow up.. on 2.6.30 I was nearly ready to say the problem had vanished but it then occurred about 25 days later..
so upgrading to 2.6.30 has at least reduced the frequency of the AlienDac linux "blast of noise with youtube" bug considerably.

[zog666]

just like to bump this problem if anyone has any ideas? It still happens every few weeks, only in youtube (still on 2.6.30 kernel).. quite annoying for what is otherwise a clean and nice sounding system to suddenly collapse into what sounds like full blast white noise.

Stopping the browser and starting it again (hence restarting flashplayer) always fixes it.

[danb1974]

Just a "me too". After days sound suddenldy turns into pure noise. I restart pulseaudio to fix this. Happens with pcm2702 but not with pcm2706 (both diy). First I thought I had a hardware issue with the former, but not I see I'm not the only one. Not sure what triggers it (no web activity when it happens). Ubuntu lucid, stock kernel 2.6.32

[zog666]

Originally Posted by danb1974

Just a "me too". After days sound suddenldy turns into pure noise. I restart pulseaudio to fix this. Happens with pcm2702 but not with pcm2706 (both diy). First I thought I had a hardware issue with the former, but not I see I'm not the only one. Not sure what triggers it (no web activity when it happens). Ubuntu lucid, stock kernel 2.6.32

I should have followed up that the problem has largely gone away for me.. however I changed PC, and upgraded Linux distro. I have still had one glitchy sound messup, but only one, in months... and it may have just been something else crashing.

The PC that was exhibiting the problem was a Dell Precision 340. As I needed to go to a PCI-E video card when we got a bigger (full HD) TV, I "upgraded" to a Dell gx280 with Lucid Lynx (10.04) Xubuntu, using pulsaudio, and the problem has vanished. I thought it was the upgrade of distro.. but maybe it is the motherboard USB chipset?



for ref heres some tech info:

root@gx280:~# uname -a
Linux gx280 2.6.32-25-generic #45-Ubuntu SMP Sat Oct 16 19:48:22 UTC 2010 i686 GNU/Linux

root@gx280:~# lsusb 
Bus 005 Device 003: ID 05af:3062 Jing-Mold Enterprise Co., Ltd 
Bus 005 Device 002: ID 08bb:2702 Texas Instruments Japan Speakers
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 003: ID 04d9:1203 Holtek Semiconductor, Inc. MC Industries Keyboard
Bus 003 Device 002: ID 045e:0040 Microsoft Corp. Wheel Mouse Optical
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 046d:c526 Logitech, Inc. MX Revolution Cordless Mouse
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

root@gx280:~# lspci
00:00.0 Host bridge: Intel Corporation 82915G/P/GV/GL/PL/910GL Memory Controller Hub (rev 04)
00:01.0 PCI bridge: Intel Corporation 82915G/P/GV/GL/PL/910GL PCI Express Root Port (rev 04)
00:1c.0 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 1 (rev 03)
00:1c.1 PCI bridge: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) PCI Express Port 2 (rev 03)
00:1d.0 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #1 (rev 03)
00:1d.1 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #2 (rev 03)
00:1d.2 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #3 (rev 03)
00:1d.3 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB UHCI #4 (rev 03)
00:1d.7 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) USB2 EHCI Controller (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev d3)
00:1f.0 ISA bridge: Intel Corporation 82801FB/FR (ICH6/ICH6R) LPC Interface Bridge (rev 03)
00:1f.1 IDE interface: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) IDE Controller (rev 03)
00:1f.2 IDE interface: Intel Corporation 82801FB/FW (ICH6/ICH6W) SATA Controller (rev 03)
00:1f.3 SMBus: Intel Corporation 82801FB/FBM/FR/FW/FRW (ICH6 Family) SMBus Controller (rev 03)
01:00.0 VGA compatible controller: nVidia Corporation GT218 [GeForce 210] (rev a2)
01:00.1 Audio device: nVidia Corporation High Definition Audio Controller (rev a1)
02:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5751 Gigabit Ethernet PCI Express (rev 01)
04:00.0 SCSI storage controller: Adaptec AHA-2940U2/U2W