Date: Wed, 15 Dec 2004 07:42:44 +0100 From: Christian Hiris <4711@chello.at> To: freebsd-questions@freebsd.org Cc: Sandy Rutherford <sandy@krvarr.bc.ca> Subject: Re: Changing hw.snd.pcm0.buffersize in 4.10. Message-ID: <200412150742.59900.4711@chello.at> In-Reply-To: <41BF6D30.8070508@nbritton.org> References: <16829.40585.759971.425967@szamoca.krvarr.bc.ca> <16831.6359.873230.920480@szamoca.krvarr.bc.ca> <41BF6D30.8070508@nbritton.org>
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On Tuesday 14 December 2004 23:46, Nikolas Britton wrote:
> Sandy Rutherford wrote:
[...]
> > >
> > > I wonder if it wouldn't be:
> > >
> > > set hw.snd.pcm0.bufffersize=N
> >
> >This doesn't work either. No error --- it just ignores the setting.
This only works, if the driver supports it. To load loader environmental
variables something like TUNABLE_INT("hw.snd.pcmN.buffersize, &...) should
show up in the driver code:
% cd /usr/src/sys/dev/sound/ && cat `ls` | grep TUNABLE_
% cd /usr/src/sys/dev/sound/isa && cat `ls` | grep TUNABLE_
% cd /usr/src/sys/dev/sound/pci && cat `ls` | grep TUNABLE_
% cd /usr/src/sys/dev/sound/pcm && cat `ls` | grep TUNABLE_
TUNABLE_INT("hw.snd.targetirqrate", &chn_targetirqrate);
TUNABLE_INT("hw.snd.verbose", &sndstat_verbose);
TUNABLE_INT_DECL("hw.snd.verbose", 1, sndstat_verbose);
TUNABLE_INT("hw.snd.unit", &snd_unit);
TUNABLE_INT("hw.snd.maxautovchans", &snd_maxautovchans);
% cd /usr/src/sys/dev/sound/usb && cat `ls` | grep TUNABLE_
This means only the tuneables hw.snd.targetirqrate, hw.snd.verbose,
hw.snd.unit and hw.snd.maxautovchans are retrieved from the loader
environment at boot time by the pcm driver. (I took this from the sources of
the RELENG_*5* branch on my system)
[...]
> Yea, I got my old laptop out that has 4.10 on it and I was rooting
> around in the src and found that, I tried everywitch way to get it to
> work in the kernel file but It nerver did work (config always bitched at
> me), I tried it also like this "make DSP_BUFFERSIZE=16384 depend && make
> DSP_BUFFERSIZE=16384 && make DSP_BUFFERSIZE=16384 install". this did not
> pruduce any errors but it didn't do anything ether, it skipped over the
> sound stuff as if there was no change, also I tried hard coding it it in
> sound_config.h but again same effect (maybe I did it wrong, i'm not a
> programmer), maybe you have to do a "complete" rebuild of the kernel and
> I did not try that because this laptop is only a P100 with 40MB Ram.
> also I found refrences to "bufsz" from /dev/sndstat so I tried adding it
> to the kernel config file like this "device sbc0 at isa? port 0x220 irq
> 10 drq 1 bufsz 16384" and config didn't like that (I never tried it with
> device pcm tho?)
AFAIK the define is named DSP_BUFFSIZE (in src/sys/dev/sound/pcm/sound.h.
DSP_BUFFSIZE can be used to define the default buffersize for sound drivers,
but most of the sound drivers use their own defines.
If you want to change the default buffersize for a sound driver you need to
search for a define like xxx_BUFFSIZE, where xxx is the name of the sound
driver (maybe some developers use other naming-conventions).
ie., if you want to change the default buffersize of the ESS driver you need
to change the line "#define ESS_BUFFSIZE (4096)" in
src/sys/dev/sound/isa/ess.c.
If you use the sbc driver, you need to do this changes in sb8.c or sb16.c,
depending on the soundcard you are using. sbc.c is only the code for the
corresponding bridge driver.
However, I'm not a guru, so I can't guess, if a driver works better with any
other buffer size defined, than the original one.
- --
Christian Hiris <4711@chello.at> | OpenPGP KeyID 0x3BCA53BE
OpenPGP-Key at hkp://wwwkeys.eu.pgp.net and http://pgp.mit.edu
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