Hi Caiwen,

On 05/10/2011 01:38 AM, Caiwen Zhang wrote:
> This patch is to fix the issue that can't attach GPRS after detach it. 
> 

I'd like to see a complete AT log of this situation if possible.  It
sounds like there's something else going on here...

> Cause:
>   When start detaching GPRS, driver_attched value is set to FALSE, if
> device registered to GPRS network during GPRS detaching, driver_attched is set to TURE.
> After that, GPRS attaching will always be ignored because driver_attched is always TURE.
> It seems the definition of driver_attched is confused.
> 
> Scenario:
>   When device is unregistered(+CREG: 2), GPRS is detached. During GPRS detaching, device
> registered to network again(+CREG: 1, xxx, xxx).

Really sounds like your firmware is too twitchy.  Why does it report
CREG: 2 and then immediately finds registration?  Is this related to
cell roaming or technology switch?

> 
> Solution:
>   variable attached represents the GPRS attach status, it only be TRUE, when CGATT=1 and 
> CGREG is registered or roaming(roaming allowed). variable driver_attached represents CGATT
> status of the driver. its value will only be changed after set_attached successfully or 
> GPRS detached notified. variable pending_attached represents the pending status of CGATT.
> 

Can you try the attached patch and tell me if this fixes your problem?

Regards,
-Denis