Re: [PATCH] option: Improve Quectel EP06 detection

From: Lars Melin
Date: Tue Sep 11 2018 - 10:00:24 EST


On 9/10/2018 18:39, Kristian Evensen wrote:
Hi,

On Mon, Sep 10, 2018 at 12:30 PM Johan Hovold <johan@xxxxxxxxxx> wrote:
Please provide the output of usb-devices (or lsusb -v) for both
"configurations". How do you update the configuration by the way?

The configuration is updated using a proprietary AT-command
(AT+QCFG="usbcfg"). The format of the command is as follows:
AT+QCFG="usbcfg",<vid>,<pid>,<diag>,<nmea>,<at_port>,<modem>,<rmnet>,<adb>.
In other words, you set which interfaces to enable/disable. Based on
my testing, it is only possible to enable/disable diag, rmnet (QMI)
and adb, as well as nmea, at_port and modem together. I.e., it is not
possible to only disable for example nmea.


If I for example disable diag, then the bInterfaceNumber of nmea
changes from 1 to 0, at from 2 to 1, etc., etc.

BR,
Kristian


This also becomes a mess for the qmi-wwan driver which has the rmnet/qmi interface hardcoded to 4 so that driver will also need a workaround.
Quectel seems to have completely missed the reason why usb id's should be unique and not reused for a different product or a different interface layout, there is already a workaround in qmi-wwan for their previous EC-20 card...
My opinion is that the option and qmi-wwan drivers should support EP06 in the factory delivery configuration and not in a configuration the user has selected with a Quectel proprietary AT cmd.
Can you give some good reason for disabling an interface instead of letting it stay but not use it if you don't need it?


Thanks
/Lars