Re: Audio skipping with alsa

[Takashi Iwai <tiwai@suse.de>]

At Wed, 10 Sep 2003 15:38:46 +0200 (CEST),
Jaroslav wrote:
> 
> On Wed, 10 Sep 2003, Takashi Iwai wrote:
> 
> > At Tue, 09 Sep 2003 15:14:21 +0100,
> > Russ Garrett wrote:
> > >
> > > Hi, I've just installed an M-Audio Audiophile 2496 sound card (Envy24)
> > > with the 2.6.0-test5 kernel (with the preemptible kernel option on),
> > > using the ice1712 alsa driver (although this also happens in 2.4.21
> > > without preemptible kernel).
> > >
> > > Music plays fine until I do *anything* - changing windows, scrolling,
> > > pressing buttons, whatever - when it stutters badly. Scrolling in an
> > > anti-aliased terminal is especially fun. However, if I play using XMMS
> > > with the realtime priority option, everything's fine, although that has
> > > the distinct disadvantage that I have to run it as root.
> > >
> > > I've tried enabling/disabling ACPI/APM/APIC. The card isn't sharing an
> > > IRQ with anything.  It's not a hard drive/IDE related issue, although
> > > that's all using DMA anyway.
> > >
> > > I do have both an AGP and a PCI graphics card installed and in use,
> > > although the stuttering happens if I do anything on either. I've found a
> > > few references to this problem on google, but no solutions. It works
> > > fine on Windows ;).
> > >
> > > Here's what happens if I try to scroll in gnome-terminal whilst aplaying
> > > something:
> > >
> > > rg@russell:~$ aplay < test
> > > Playing raw data 'stdin' : Unsigned 8 bit, Rate 8000 Hz, Mono
> > > xrun!!! (at least 869.990 ms long)
> > > xrun!!! (at least 21.552 ms long)
> > > xrun!!! (at least 17.686 ms long)
> > > xrun!!! (at least 16.482 ms long)
> > > xrun!!! (at least 17.194 ms long)
> > > xrun!!! (at least 17.126 ms long)
> > > xrun!!! (at least 14.123 ms long)
> > > xrun!!! (at least 13.679 ms long)
> > > xrun!!! (at least 12.928 ms long)
> > > [...and so on, for another 20 or so lines]
> >
> > i guess it's a general scheduler issue.
> >
> > why you face this problem more severly than others:
> > the timing on the ice1712 (envy24) chip is quite tight, because it
> > always needs 32bit * 10 channels interleaved samples even if you want
> > to play a two-channel mp3 file.  more badly, the maximum buffer size
> > is limited to 64k byte.  hence, at most, you can get about 0.1 sec for
> 
> It's limited to 256kB. And yes, it's only 0.14 sec for 44.1kHz playback.

oh yes, thanks for correction :)


Takashi