Re: Sound skips

[Geert, Cort - the question for you guys is "has the Console IRQ block been
solved?" - I was under the impression it had from some traffic on
Linux-audio-dev]

Mon, Mar 26, 2001,  Giuliano Pochini wrote:

quoted

quoted

Ok, I'll try, but this problem regards interrupt latency,
not user-spacelatency.

can you be sure it is IRQ and not scheduling latency?

No, but it's likely to be. The audio buffer is 32 fragments (2KB),
that is 1.48s. I don't think an app can remain blocked so long

an FB scroll would block my G3/beige for 1.9 sec! (but YMMV).

and it
doesn't explain why libtool blocks the sound since it executes in much
less time than one second.

no it doesn't... hmmm interesting... but see below:

--

for dmasound: regardless of how many fragments are buffered only two (max)
will be queued for dbdma - so IRQs blocked for longer than 23-ish ms will
skip with that setup.

[the IRQ routine deals with queuing fragments written by the app but not yet
 queued for dbdma]

In addition - unless the app can write all 32 fragments ahead - if *it* is
blocked (by scheduling latency) this will also cause the same effects.

quoted

If so, can you
identify what driver or function is holding off IRQs for this length of
time? [a few hundred ms is a 'monstrous' time to hold IRQs off].

Console scrolling does it IFAIK, but this is not the case.

Yes, console is/was a bad offender - but I thought that the IRQ block in
that had been solved...

Cort? Geert?

ciao,
Iain.

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On Mon, 26 Mar 2001, Iain Sandoe wrote:

[Geert, Cort - the question for you guys is "has the Console IRQ block been
solved?" - I was under the impression it had from some traffic on
Linux-audio-dev]

According to Andrew Morton it is. That's all I can say :-)

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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