GSM modem - just ERROR

[Harald Welte]

On Fri, Mar 16, 2007 at 03:03:13PM +0100, Nils Faerber wrote:

> Back to the ringtone...
> Yesterday I tried a voice call which worked quite nicely. But only after
> pulling almost all output mixers to 100% I was able to get a reasonable
> playback volume so that I could clearly understand my partner while
> holding the NEO to my ear.
> If this is really all volume one can get from the single builtin speaker
> then I fear I will miss many calls and will probably also never see a
> free speaking feature on the NEO.
> 
> So to the question a little differently (now that I know that there is
> only one speaker built-in ;)
> 	Is there a way to amp the output of the internal speaker to a level
> that is audible without holding the NEO near to my ear?

yes, you can just use the two loud stereo speakers instead of the
receiver speaker :)

> I am not sure how other phones do that in hardware... do they use a
> second speaker for ringer and free speaking?

yes, we're actually having two 'second' speakers and a 1.2Watts
amplifier for that.

> If there is such thing it would be great to have a (brief) document
> describing the hardware, i.e. which parts are there, how they are
> connected and why it was done the way it was done. This would help to
> understand the hardware and how it can be used/programmed.

I would love to have such a document myself.  Unfortunately even I have
to manually 'reverse-engineer' the changes by visuall comparing
schematics of different revisions. 

Especially the "why it was done" a particular way is a question that I
keep asking myself about dozens of things, without being able to come up
with any apparent or logical reason.

The whole hardware situation is a real mess, I have to admit.

This combined with a severe lack of staff, skills and time.... => I
don't think there will be any public document on the hardware any time
soon. 

Also, things keep changing, and we yet have to see a hardware revision
that completely works :(

FIC will probably not like me talking about this that openly - but
seriously, we're not doing much else than fire-fighting hardware
problems for half a year now.  There are lots of plans how to do it
better with the next devices on the roadmap.  But for now, we're still
stuck with the current situation.

Let's hope GTA01Bv4 will solve all of the known bugs, and we have a
hardware revision that we can actually produce reliably in quantity.

> And congratulations for the kernel port - having done such thing myself
> I think you did a pretty good job abstracting the hardware properly.
> That's good!

thanks, I'm not entirely happy yet, but it works for the time being ;)

Particularly crude is the PMU driver.  All voltage settings, etc. need
to be put in a platform_data structure that is specific to the neo.  The
pcf50606.c should not make any assumptions about being inside a Neo1973
device.  It should further provide something like an 'IORESOURCE_POWER',
which is then used by neo1973 platform devices and passed on to the
actual drivers.

Basically, power needs to be treated equal to any otehr resource such as
memory, GPIO, IRQ, ...

-- 
- Harald Welte <laforge at openmoko.org>          	        http://openmoko.org/
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Software for the world's first truly open Free Software mobile phone