GPRS re-connect problem

GPRS re-connect problem

[August Mayer]

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Hello,

When connecting again to GPRS / PPP, after an Internet connection has 
been closed previously, the connection seems to fail. It looks like the 
ofono_modem serial data channel is completely closed when a PPP 
connection is shut down. I'm using a Telit Modem, which provides several 
serial ports, and am right now using separate serials for the AT chat 
and the data/PPP; for this reason, the AT chat continues working, but 
the data channel is dead.

My question is, is it somehow necessary to re-initialise the modem data 
serial channel after a PPP connection? Or could there be a conceptual 
problem that I have overlooked?

Many thanks & greetings       August


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Re: GPRS re-connect problem

[Denis Kenzior]

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Hi August,

On 06/21/2012 05:51 AM, August Mayer wrote:
> Hello,
>
> When connecting again to GPRS / PPP, after an Internet connection has
> been closed previously, the connection seems to fail. It looks like the
> ofono_modem serial data channel is completely closed when a PPP
> connection is shut down. I'm using a Telit Modem, which provides several
> serial ports, and am right now using separate serials for the AT chat
> and the data/PPP; for this reason, the AT chat continues working, but
> the data channel is dead.
>

Something similar was happening on Qualcomm based modems from Huawei, 
ZTE, etc.  The modem was sending a HUP on the PPP channel after PPP link 
was dropped.  I believe the preferred solution was to send AT&C0 when 
initializing that port.

> My question is, is it somehow necessary to re-initialise the modem data
> serial channel after a PPP connection? Or could there be a conceptual
> problem that I have overlooked?
>

This can be possible as well.  See commit 
7ed56d6844f8131cbf981e482b7bded8b20db7ab for another possible solution 
(prior to &C0) that can be used as well.

Regards,
-Denis

Re: GPRS re-connect problem

[August Mayer]

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Hello Denis,

Wow, that was it exactly! After initialising with AT&C0, the serial data 
connection isn't closed anymore. Never thought that the close would 
originate from the modem!

Many thanks for your help & greetings     August


Am 2012-06-19 10:30, schrieb Denis Kenzior:
> Hi August,
>
> On 06/21/2012 05:51 AM, August Mayer wrote:
>> Hello,
>>
>> When connecting again to GPRS / PPP, after an Internet connection has
>> been closed previously, the connection seems to fail. It looks like the
>> ofono_modem serial data channel is completely closed when a PPP
>> connection is shut down. I'm using a Telit Modem, which provides several
>> serial ports, and am right now using separate serials for the AT chat
>> and the data/PPP; for this reason, the AT chat continues working, but
>> the data channel is dead.
>>
>
> Something similar was happening on Qualcomm based modems from Huawei, 
> ZTE, etc.  The modem was sending a HUP on the PPP channel after PPP 
> link was dropped.  I believe the preferred solution was to send AT&C0 
> when initializing that port.
>
>> My question is, is it somehow necessary to re-initialise the modem data
>> serial channel after a PPP connection? Or could there be a conceptual
>> problem that I have overlooked?
>>
>
> This can be possible as well.  See commit 
> 7ed56d6844f8131cbf981e482b7bded8b20db7ab for another possible solution 
> (prior to &C0) that can be used as well.
>
> Regards,
> -Denis
>
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>


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