[linux-audio-user] Ardour, Jack, and 2.6 kernels + XRuns with the Audiophile 24/96 M-Audio
cv223 at comcast.net
Mon May 31 23:00:47 EDT 2004
Aha, a thread convergence!
I started the "Ardour..." thread lamenting long xruns under the 2.6
kernels. Based on recommendations on the list, I went back to a 2.4
kernel, still having the occasional long xrun. In the "XRuns..."
thread, the following from a post by Jan Depner caught my eye:
"What kind of disk drives? Adaptec SCSI controllers can give you
problems with xruns."
Uh-oh. I'm using an Adaptec controller on my main board (a 7890). With
a little digging, I came up with the following from the ST Audio website
"The famous Adaptec 2940 SCSI controller series is causing performance
problems when installed in the same system as our DSP24 series and when
the audiodata is stored on a SCSI-HDD connected to the controller. To
get good results in benchmark tests, the Adaptec controller keeps steady
access to the PCI bus. The result is a reduction of data transfer of
other PCI cards like the DSP24 hardware. This means that the ASIO/MME
buffer size (which is the latency) needs to be set to a relative high
value to avoid stuttered audio playback and drop-outs during recording.
The performance problems can be reduced if both the DSP24 and the
Adaptec controller both have a unique and unshared IRQ. Still the
performance will not be as good compared to the regular onboard
IDE-controller of a modern mainboard. This means that the best solution
is to use a IDE-HDD to save the audiodata from within your recording
software. The simple presence of the controller (that is used while the
audiodata is stored on a IDE-HDD) is no problem."
Uh-oh again. The 7890 is the on-board version of the 2940. I thought I
had the xruns pretty much under control with the 2.4 kernel, then I
picked up a M-Audio Delta 1010LT (I was jonesing for the 8 channels of
input!). Ugh. I can't record more than a few seconds of 8 channel
input before a 100msec+ xruns brings everything to a halt. Even
recording 2 channels won't make it through a 4:00 min song.
So, am I completely hosed with my Adaptec SCSI drive setup? Anybody
have any insight into these Adaptec controllers? I've fussed with the
setpci latency_timer settings (from Jan Depner's "Installing and
configuring ALSA, JACK, & Ardour..." web site), but still see long
xruns. Trying an IDE drive is not that simple, as I don't have any
drive slots left in the box (I've got 4 SCSI drives setup as a RAID).
So, I'd like to exhaust all possibilities before trying new drive
Any thoughts/ideas/suggestions would be _greatly_ appreciated!
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