On 26-Jul-2004 Don Lewis wrote: > On 26 Jul, 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? > > Hmn, looks bogus to me. I think the intention is to round timeout up > to 1 if the result of the formula is zero. The final assignment > statement looks bogus to me. Maybe a too short timeout is the > source of this problem. > > It looks like this assignment appeared in rev 1.65. Hmm, your guess is as good as (or probably better than) mine. :-) A little more in the way of comments certainly wouldn't hurt. >> 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 don't know. I'm having no small difficulty understanding this >> code, but these two items caught my attention. > > I ran into the same problem when I was looking at the code a few days > ago. > > BTW, the trace output that was posted showed write() returning 0 > immediately before the failure occurred. Are you referring to the truss output I posted a few days ago? The thing of it is, though, that the original "channel dead" message had already occurred in a previous run of madplay (which wasn't traced), so it's really hard to say if there's any useful info to be obtained from tracing a later run, after the pcm device was already "broken". So far, I still haven't gotten the error with the new kernel I'm testing. I wouldn't say absolutely that that single patch (of the final conditional test) is "the fix", but it may help in the meantime. -- Conrad J. Sabatier <conrads_at_cox.net> -- "In Unix veritas"Received on Mon Jul 26 2004 - 20:15:25 UTC
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