[Gta04-owner] Modem crashing?

Dr. H. Nikolaus Schaller hns at goldelico.com
Sat Feb 18 11:44:03 CET 2012

Am 18.02.2012 um 07:08 schrieb NeilBrown:
> If I call my GTA04, answer the call, and then hang up, I do not get 
> on the 'Application' port (which is where I get e.g. "RING" indications).
> However I *do* get "NO CARRIER" on the Modem port.
> A little surprising but possibly quite usable.  There may be other surprises
> for those willing to explore.
> When I dial out it seems a little different.  I try to hang up with ATH
> but "AT+CPAS" indicates I am still on a call.  When the other end hangs up,
> then I get NO CARRIER.
> I'm not sure if this is always consistent.  More experimentation is needed.

I have recompiled the hso driver with debug enabled and could no longer see
the USB re-enumeration issue (which does not prove that one has to do anything
with the other, i.e. this is a step towards a solution).

But I can confirm that the "NO CARRIER" message is there. And I also did
see it on an outgoing call if the called party ends the call. I.e. it comes
independently of who has initiated the call.

Both times the message appears on the /dev/ttyHS_Modem port.

It also works to answer an incoming "RING" with ATA and hang up
with AT+CHUP. If I do a AT+CHUP after "RING", the call is terminated
with a busy indication on the remote phone.

So the firmware bug may reduce to the modem sending the "NO CARRIER"
to the wrong interface. I.e.. the correct workaround is to monitor both and
merge the messages. Then, we don't need polling.


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