Questionable code in sys/dev/sound/pcm/channel.c
Conrad J. Sabatier
conrads at cox.net
Mon Jul 26 14:47:11 PDT 2004
On 26-Jul-2004 Conrad J. Sabatier wrote:
> I'm a little perplexed at the following bit of logic in chn_write()
> (which is where the "interrupt timeout, channel dead" messages are
> being generated).
>
> Within an else branch within the main while loop, we have:
>
> else {
> timeout = (hz * sndbuf_getblksz(bs)) /
> (sndbuf_getspd(bs) * sndbuf_getbps(bs));
> if (timeout < 1)
> timeout = 1;
> timeout = 1;
>
> Why the formulaic calculation of timeout, if it's simply going to be
> unconditionally set to 1 immediately afterwards anyway? What's going
> on here?
>
> Also, at the end of the function:
>
> if (count <= 0) {
> c->flags |= CHN_F_DEAD;
> printf("%s: play interrupt timeout, channel dead\n",
> c->name);
> }
>
> return ret;
> }
>
> Could it be that the conditional test is wrong here? Perhaps
> we should be using (count < 0) instead?
I'm now running a kernel built with this last conditional test changed
to "if (count < 0)" and sound is still working OK. Have yet to see if
this eliminates the interrupt timeout messages. Perhaps a few other
people might try it and see?
I still don't know what to make of the earlier business with the
setting of "timeout". Looks to me like something that just got
overlooked in the course of a series of edits.
--
Conrad J. Sabatier <conrads at cox.net> -- "In Unix veritas"
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