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Re: [olpc-software] Source repository access

On 3/26/06, Jim Gettys <jg laptop org> wrote:
> On Sun, 2006-03-26 at 20:24 +0800, Jaya Kumar wrote:
> >
> > AD1888 support in ALSA seems complete to me. Are you having a specific
> > problem with it?
> It works as far as it goes, as far as we know.
> However, it could go further ensuring parts of the chips not in use are
> off, and more importantly, entirely powering the chip off when not in
> use, which the 1888 is capable of, and many other chips are not able to
> do.

I have a couple of questions here. Are you planning to use the 2.6.16
cs5535audio driver for your first rev boards? The PM support I posted
goes as far as turning off the AC Link. The upper layer of ALSA
suspend has the responsibility for disabling the codec on the other
side. Currently what ALSA does is to shutdown the following: EAPD, HP
Amp, ADC & DAC, Analog Mixer with Vref On. I suppose it could go
further but that would involve testing whether it resumes properly. I
could add a ad1888 specific build_ops->suspend in the codec layer to
shutdown completely. I'd need someone to test this for me since
nothing here seems to use the AD1888. Unless of course you're willing
to ship a test board to India.

> As you might imagine, we care a whole lot about what our minimum power
> consumption is, since the CPU will be able to suspend to RAM while

Just to be certain, are you using the GX2 or the GX3 cpu on your first
rev boards? Are you using the CS5535 or the CS5536 bridge?

> keeping the display running (using our DCON chip).  So our bottom end
> power consumption when, say, reading a book and not doing anything,
> should be in the neighborhood of .5 watts; even if we continue to

Impressive goals.

> forward packets in the mesh, (which we can also do with the CPU
> suspended, due to the choice of the Marvel wirless chip), we'll be in
> the neighborhood of 1 watt.

Do you already have drivers for all this stuff? I'd be happy to help
in that area.

> So power consumption that would be lost in the noise on most systems
> will be very significant on our system.  We'll be in the values normally
> only seen on PDA's.
>                               Regards,
>                                   - Jim
> >
> > There are other items on your kernel work list that look attractive to
> > me. Let me know if you actually need help on them or already have
> > people to work on them.
> >
> > Best regards,
> > jayakumar
> > --
> > olpc-software mailing list
> > olpc-software redhat com
> > https://www.redhat.com/mailman/listinfo/olpc-software
> --
> Jim Gettys
> One Laptop Per Child

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