What now? How to proceed debugging this GSM/kernel problem?

Joachim Steiger roh at openmoko.org
Mon Apr 21 14:51:57 CEST 2008

Mike (mwester) wrote:
>  So close.  So very close...
> I've been expending much effort in fixing up the many suspend/resume
> issues that have been crippling the poor GTA01.  At this point, the
> major ones are all resolved, but I've encountered a difficult one.
> So I have questions.  This email is long, so for those with shorter
> attention spans I'll cut to the chase:

thanks a lot. still feeling a bit sick, so i will only answer what i
know now.

> a) Where is the list of known problems with the different GSM modem
> firmwares, and the list of fixes in each firmware?

we hace such a list at openmoko, but i dunno about the release ability,
will follow that up internally and report back.

> b) Is there a document that describes what we (or anyone else, for that
> matter) know about the problems or unexpected behavior of our version of
> the S3C2410 SoC UARTs, especially with regard to auto flow control and
> overruns?

> c) What are the real-world parameters for the GSM modem with regard to
> flow-control:
>   1) How much data can it buffer internally?
>   2) What does it do when its internal buffers fill -- does it throw
> data away?  Does it transmit despite being flow-controlled?  Is there an
>  AT command available to alter or control how it behaves?  Can it report
> internal buffer overflows?  What could trigger it to transmit despite
> being flow-controlled?

dunno, but good questions. sean c. should be able to answer that. ccing him.

>   3) Do different firmware versions for this modem behave differently in
> regard to flow control, and if so, how so?

afaik not

> d) If I were to acquire a scope, are the CTS, RTS, and other signals
> between the GSM and the UART accessible on the debug board?  Are there
> pads on the phone itself?
not on the debugboard, but on the device itself. should be labeled, but
in case you want to really do that, just holler.

> e) Can we do anything with gsmd, and/or phonekit, to work around the
> problem in the meantime?


Joachim Steiger
developer relations/support

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