USB audio bumpy

[MatB]

Hi,
I have a wl-500gx running the last firmware and a trust "2010 usb soundforce" audio dongle connected directly to the box.
While playing, from time to time, i hear a gap of half a second or less.
In the syslog i get:

kernel: usb-uhci.c: iso_find_start: gap in seamless isochronous scheduling

This happens with both madplay and the built in waveserver.
I tried with different mp3 bitrate, different file location (also from ramfs) and different process priority (snice -20), but the problem persists.
I also killed many unused process, and it got a little better.

I'm using madplay, the static linked executable from this thread:

http://wl500g.info/showthread.php?t=1866&highlight=madplay

When it starts, madplay says:

MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
output: sample frequency 44100 Hz not available; using 48000 Hz
output: resampling 44100 Hz to 48000 Hz

Could it be a soundcard problem? I don't want to spend 50 euros for a SB card and being stuck with the same problem.
Any idea/suggestion?

MatB

[Styno]

Perhaps adding an USB harddisk with a swap partition could help?

[MatB]

Perhaps adding an USB harddisk with a swap partition could help?

I don't think this is the case, i have around 13 megs free...
I wonder if i'm the only one with this problem.
Thanks anyways,

MatB

[WlanMan]

Hi

The error comes from the ohci driver (http://www.charmed.com/txt/usb-uhci.txt) and i think it just means the incoming data stream hast a gap, some sort from out of snyc when i see the code right.
It may be the soundcard, do you know which chipset is in it ? Are there reported problems on google ? Linux sound driver uses the standart HID norm which many soundcards do not honnor correctly (so there are quite many detections/fixes for various webcam microphones and other devices in the code).

If the sblive works for others, you can try it. i use a 6$ ebay soundcard with CM108 Chipset on 500g which works flawless...

Greets

[MatB]

Hi WlanMan, thanks for the answer.
I could not find any infos, so i dissected it. ;)
The chip inside is a CM102s, which is reported as OK here: http://www.nslu2-linux.org/wiki/HowTo/SlugAsAudioPlayer
Does your chip support 44100hz mode, or madplay is resampling to 48k also in your configuration?
I'm running out of ideas...

MatB

PS: I guess you meant uhci, not ohci...

[WlanMan]

Hi

I cant remember if it had to do resampling, i hope it didn´t since the cm108 is the newest of cmedias low-cost series. But since resampling should´nt create much problems, especial on the 500gx i cant think of as this is the problem. Do you habe some linux-pc to try it out there ?
As i cant find any bug reports about the given error that give usable information, and dont have the device i just guess the problem.

Do you have the soundcard with the hd on separate ports ? If not this could be the problem forcing the hd down to 1.1 speed...

Greets

[MatB]

Do you habe some linux-pc to try it out there ?
I tried it on a Debian box, kernel 2.4.27: it works flawlessy.

Do you have the soundcard with the hd on separate ports ? If not this could be the problem forcing the hd down to 1.1 speed...
Sure, this is one of the first thing i tought of.
Right now i the audio dongle is connected to the rightmost USB port, and the 'hiccup rate' is almost accettable.
So i guess it was a priority problem on the USB interface... either that or the dongle likes Keith Jarrett ;)
Thanks a lot for the great support.

MatB