Re: cs4248 / thinkpad 755 / 755c , patch suggestions [PATCH]]

[Takashi Iwai <tiwai@suse.de>]

At Tue, 8 Jul 2003 08:58:21 -0500,
Ryan Underwood wrote:
> 
> 
> Hi Takashi,
> 
> On Tue, Jul 08, 2003 at 12:50:05PM +0200, Takashi Iwai wrote:
> > 
> > > One issue is to note, I don't know if this is a problem with the ad1848
> > > driver in general or what; if I cat a 11025hz mono 8-bit file to
> > > /dev/dsp, the sound comes out verrrrry slllloooowwwllly.   But using
> > > aplay, it works fine.
> > 
> > could you check the parameters in /proc/asound/card0/pcm0p/sub0/*
> > during playback via oss?
> 
> The results are pasted below -- what is strange is that aplay identifies
> the file as 11025Hz but apparently the OSS driver thinks it is 8000Hz
> data.
 
ah, i understand.  you cannot cat to /dev/dsp in general.
if you do this, it's supposed to be 8kHz mono samples.


> > > I am not sure the best way to test the power managmeent code -- it
> > > doesn't crash the machine at least. ;)
> > 
> > it looks ok - but i guess we need to restore the registers (mixer
> > status, etc) too.
> 
> You are right -- I just checked the registers before and after flipping
> that bit, and it seems they are set to default values afterwards, which
> would seem to support the possibility that this is a power management
> feature.
> 
> The main thing I was wondering about is if some other machine with a
> AD1848 goes into D0 for instance, and the suspend function does nothing
> (since it is not a thinkpad), is the system still in an ok state as long
> as the card's status is not set to D0 when the card is actually not in
> D0?  Does that make sense?

if the chip supports really something the power management, we should
implement it, too.  but AFAIK, ad1848 itself has no such a control.
so, the suspend callback is expected just to save the last status so
that it can be restored in the resume callback.


Takashi


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