2017-11-20 09:43:30

by Bjørn Mork

[permalink] [raw]
Subject: Re: [PATCH] net: qmi_wwan: add Dell DW5818, DW5819

Shrirang Bagul <[email protected]> writes:

> Dell Wireless 5819/5818 devices are re-branded Sierra Wireless MC74
> series modems which will by default boot with vid 0x413c and pid's
> 0x81cf, 0x81d0, 0x81d1,0x81d2. Along with qcserial, these modems support
> qmi_wwan on the usb interface #12.

NAK,

Interace #12 is MBIM, as shown by the device descriptors. Please provide
those descriptors and you will see that this interface is clearly a CDC
MBIM class interface.

Yes, I know these modems probe the control protocol so that you can make
QMI work on an MBIM control interface by sending it a QMI request as the
first messsage. This is still wrong, abusing a quirky firmware
feature.

You need to reconfigure the modem for QMI using the Sierra specific AT
command or QMI request (tunneled in MBIM!) to properly switch it to QMI
mode, which will appear as a vendor specific interface number 8 (and 10
if you enable both QMI functions).





Bjørn

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