usb_modem and mbimcli

[Pirmin Duss]

Hello Christian

Thanks for your teams brainstorming and sharing of information.

I will try to run mbimcli on linux, and debug on Genode once I have 
finished my current task.

Regards,
Pirmin

On 11/3/21 09:08, Christian Helmuth wrote:
> Hello Pirmin,
> 
> we had an offline brainstorming in the Genode Labs team about the
> issue you raised. Unfortunately, we could not come up with a concrete
> suggestion how you could tackle the timeout. It seems timeouts happen
> sporadically during communication with the SIM card depending on the
> platform and modem device used. This hints that Linux tools may also
> face such issues and it may be worth to investigate the behavior when
> controlling the modem on a Linux host. Building and instrumenting the
> mbimcli tool for Linux should not be too hard.
> 
> On Mon, Oct 25, 2021 at 15:37:35 CEST, Duss Pirmin wrote:
>> In rare cases the following message also appears in the output:
>> ```
>> [init -> usb_modem_drv] dev_err: nonzero urb status received: -EPIPE
>> ```
>> I'm not sure if it is related, but as the modem is connected via USB it
>> could be.
>>
>> The device is connected to a iMX8m mini, which uses the same
>> `usb_host_drv` as the iMX6q sabrelite.
> 
> The message comes from cdc-wdm.c that also includes the following
> comment, which hints a temporary (?) USB stall.
> 
>     * Avoid propagating -EPIPE (stall) to userspace since it is
>     * better handled as an empty read
> 
> Regards
> 

-- 
Pirmin Duss
Founder and Senior Software Engineer
gapfruit AG
Baarerstrasse 135
CH-6300 Zug
+41 79 683 61 84
pirmin.duss at gapfruit.com