On Wed, Jul 21, 2010 at 04:11:07PM +0400, Dmitrij D. Czarkoff wrote:
quoted text
> Jacob Meuser <jakemsr@sdf.lonestar.org> wrote:
> 
> > you're saying the volume made a difference in how often there were
> > underruns?  that is quite odd.  hmmm.
> 
> Well I'm saying that I had less underruns while being at 150/255 volume. It
> might be a coincidence.
> 
> > > At the moment of volume switching I also hear the drops (as far as I can get,
> > > the drops of a higher of switching volumes either on gettting volume lower or
> > > higher).
> >
> > that is strange too.  I have, somewhere, a program that twiddles every
> > control on the mixer as fast as possible, several thousand mixer set/get
> > cycles a second, and it hassn't caused dropouts on machines I've run
> > it on.
> 
> Well, that's what I'm quite sure about. The drops accure on every volume
> switch I performed.
> 
> > do you have clock issues?  are you running ntpd?
> 
> I'm running ntpd and it is quite active in switching time.
> 
> Well, after pkilling ntpd I got 13 drops (with 8 of them long enough to
> distinguish start and end speaker "cklicks") during 3 minutes with actually
> close output:
> 
> % ./audrops 
> pre=16 ch=2 bpf=4 block_size=4096 rate=48000 block_usec=21333
> early return at 1279713267.091162: 399 < 21333
> early return at 1279713267.091246: 84 < 21333
> late return at 1279713267.968778: 558599 > 21333
> late return at 1279713276.422734: 564385 > 21333
> late return at 1279713283.216141: 573650 > 21333
> early return at 1279713283.219052: 2911 < 21333
> late return at 1279713293.508187: 561489 > 21333
> late return at 1279713313.472366: 578602 > 21333
> late return at 1279713330.094540: 560445 > 21333
> early return at 1279713330.094700: 160 < 21333
> early return at 1279713330.094787: 87 < 21333
> early return at 1279713330.094890: 103 < 21333
> early return at 1279713330.095015: 125 < 21333
> early return at 1279713330.095142: 127 < 21333
> early return at 1279713330.095211: 69 < 21333
> early return at 1279713330.095286: 75 < 21333
> early return at 1279713330.095353: 67 < 21333
> early return at 1279713330.095422: 69 < 21333
> early return at 1279713330.095490: 68 < 21333
> early return at 1279713330.095558: 68 < 21333
> early return at 1279713330.095626: 68 < 21333
> early return at 1279713330.095694: 68 < 21333
> early return at 1279713330.095760: 66 < 21333
> early return at 1279713330.095828: 68 < 21333
> early return at 1279713330.095895: 67 < 21333
> early return at 1279713330.095963: 68 < 21333
> early return at 1279713330.096030: 67 < 21333
> early return at 1279713330.096097: 67 < 21333
> early return at 1279713330.096165: 68 < 21333
> early return at 1279713330.096233: 68 < 21333
> early return at 1279713330.096301: 68 < 21333
> early return at 1279713330.096368: 67 < 21333
> early return at 1279713330.096436: 68 < 21333
> early return at 1279713330.096503: 67 < 21333
> late return at 1279713353.314772: 569539 > 21333
> early return at 1279713353.321255: 6483 < 21333
> late return at 1279713355.167678: 566406 > 21333
> early return at 1279713355.177299: 9621 < 21333
> late return at 1279713372.491682: 567395 > 21333
> early return at 1279713372.500329: 8647 < 21333
> late return at 1279713400.362901: 555313 > 21333
> late return at 1279713412.040398: 563321 > 21333
> early return at 1279713412.040537: 139 < 21333
> early return at 1279713412.040624: 87 < 21333
> early return at 1279713412.040693: 69 < 21333
> early return at 1279713412.040763: 70 < 21333
> early return at 1279713412.040830: 67 < 21333
> early return at 1279713412.040904: 74 < 21333
> early return at 1279713412.041010: 106 < 21333
> early return at 1279713412.041079: 69 < 21333
> early return at 1279713412.041155: 76 < 21333
> early return at 1279713412.041221: 66 < 21333
> early return at 1279713412.041289: 68 < 21333
> early return at 1279713412.041357: 68 < 21333
> early return at 1279713412.041425: 68 < 21333
> early return at 1279713412.041491: 66 < 21333
> early return at 1279713412.041560: 69 < 21333
> early return at 1279713412.041628: 68 < 21333
> early return at 1279713412.041696: 68 < 21333
> early return at 1279713412.041764: 68 < 21333
> early return at 1279713412.041832: 68 < 21333
> early return at 1279713412.041899: 67 < 21333
> early return at 1279713412.041966: 67 < 21333
> early return at 1279713412.042034: 68 < 21333
> early return at 1279713412.042101: 67 < 21333
> early return at 1279713412.042169: 68 < 21333
> early return at 1279713412.042237: 68 < 21333
> early return at 1279713424.960047: 7609 < 21333
> late return at 1279713427.759535: 559467 > 21333
> late return at 1279713440.156372: 561392 > 21333
> ^Cpre=16 ch=2 bpf=4 block_size=4096 rate=48000 block_usec=21333
> bytes written = 34062336
> bytes processed = 33849344
> bytes errors = 204800
> bytes buffered = 8192
> 34062336 == 34062336 ?
> run time = 183.256628 s
> avg rate = 46177
> 
> > this is about the simplest possible audio application.  no reading
> > data from disk, not synthesizing the samples.  I don't see how
> > this could have underrun so much.  what else was running while you
> > ran this?
> 
> Aside from default processes of 4.7 I had ifstated, X11, cwm, ntpd, rtorrent
> (with 7.1/0.6 kbps loadi) and a shell script that sleeps 30 seconds and sends
> ifconfig command to the system after that. That's all.
> 
> > one final question, do you have any sort of power management features
> > enabled in the BIOS?
> 
> Well, my BIOS is very tiny, it doesn't ask about power management. Still, I
> have apmd running "Cool mode".
> 
> > hmmm, if the codec is somehow under powered, I guess that could explain
> > the correlation between higher volume and more dropouts?  maybe?
> 
> Don't think so as I had Linux on this box before, and had no single problem
> with sound. The default OS was Windows, but I only had it on twice, the last
> time on power appliance.
> 
> > iirc, you have an eapd mixer control.  have you tried switching that
> > to off?  I've heard rumors that these are sometimes inverted ...
> > eapd (external amp power down) is a tricky name.
> 
> I tried turning it off. That muted my system. After turning on I returned to
> the previous state.
> 
> By the way, do You actually know, what is eapd supposed to be used for?

yes, it's a power saving feature.  it turns off the power to an
amplifier.  that's why setting it to "off" mutes your outputs.

you probably need the changes in src/sys/dev/pci/azalia.c rev 1.169.  I
thought that was in 4.7, but now that I look, it was a bit after.

http://www.openbsd.org/cgi-bin/cvsweb/src/sys/dev/pci/azalia.c.diff?r1=1.168;r2=1.169

-- 
jakemsr@sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org