On Sat, 27 Dec 2003, Paul Davis wrote:

> >yOn Sat, 27 Dec 2003, Paul Davis wrote:
> >
> >> >i've been getting my laptop with an ICH soundchip up to speed, and i
> >> >just noticed for the first time yesterday that ALSA fails to get the
> >> >speed to the rate that JACK requests. a quick google reveals that the
> >> >OSS drivers only support 1 h/w rate, but there are suggestions that
> >> >the ALSA driver works better. however, neither JACK nor alsaplayer can
> >> >set the rate on my card to 44.1kHz - its stuck at 48kHz.
> >> >
> >> >this is alsa 1.0.0rc2 from Planet CCRMA. any clues?
> >> 
> >> this is using the snd-intel8x0 module. the wiki page has alerted me to
> >> the ac97_clock option, but it seems ludicrous to have to rmmod &&
> >> modprobe the module just to switch rates ...
> >
> >The ac97_clock option is for situation when another master clock crystal
> >than standard one is used by hardware vendor. You cannot change the real
> >rate with this option.
> >
> >It seems that your AC97 codec does not support VRA (variable rate) so it 
> >is capable only 48kHz or we have a bug somewhere.
> >
> >Can you send me contents of /proc/asound/card0/codec97* files?
> 
> i am entirely willing to believe that it can only do 48kHz. its a
> laptop (HP Pavilion), well known for having crapola audio interfaces
> and relying on s/w to make things work. here's the codec97* file
> (below).
> 
> meanwhile, i have found that the plughw layer doesn't work with JACK
> anymore. it appears that any attempt to set the period size fails. any
> ideas about that?
> 

> Extended ID      : codec=0 rev=2 AMAP DSA=0 SPDIF
> Extended status  : PRL PRK PRJ PRI SPCV SPDIF=7/8

OK, no VRA, so you have only 48kHz hardware.

Keep in mind that the intel8x0 driver must have period sizes with power of
two. When 44.1kHz -> 48kHz resampling is done, the period size requested
from application must be multiplied with this coeficient, too. But the 
period_size_near function should work (or not? - then a bug is somewhere).

                                                Jaroslav

-----
Jaroslav Kysela <[EMAIL PROTECTED]>
Linux Kernel Sound Maintainer
ALSA Project, SuSE Labs


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