[PATCH 2/4][RFC] gatchat: Allow cancelling a running command.

[Andrzej Zaborowski]

Hi Denis,

On 30 April 2010 04:53, Denis Kenzior <denkenz at gmail.com> wrote:
>> Users need to be extra careful using the cancel functions because
>> there's a potential race condition where an OK or ERROR for the command
>> being cancelled arrives just the same moment the next command in the
>> queue is being submitted, and is treated as a response to that command.
>
> This is why this is just a really bad idea.  The only one I think we should
> cancel (and most vendors support reliably) is an ATD...

You're right, the only modem it seems to work on is the Calypso now
that I've tried a bunch of different ones.

Let's skip this patch.

>
> Are you sure your CSIM STATUS poll would actually time out or would the modem
> return a +CME/+CMS error?  In the end the modem does this polling itself...

In practice they'll return errors, though according to the specs, we
should be assuming the card is not there if we get no response for N
seconds.

On the Ericsson F3607 I found it'll actually fake a response with
status word 148,4 when card is not inserted, and doesn't do polling,
i.e. insertion can only be detected if you re-connected the modem, and
extraction only when you issued a command and the modem couldn't reach
the card to perform the command.

Regards