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From:   Seunghun Han <kkamagui@gmail.com>
Date:   Thu, 4 Aug 2022 20:04:39 +0900
Message-ID: <CAHjaAcQXfNOdK7b=bx1qLwgqm5jg5N+PRbrn4OJjEYJSqwrvNw@mail.gmail.com>
Subject: Re: [PATCH] net: usb: cdc_mbim: adding Microsoft mobile broadband modem
To:     Daniele Palmas <dnlplm@gmail.com>
Cc:     Oliver Neukum <oliver@neukum.org>,
        David Miller <davem@davemloft.net>,
        linux-usb <linux-usb@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Hello Daniele,

On Thu, Aug 4, 2022 at 4:07 PM Daniele Palmas <dnlplm@gmail.com> wrote:
>
> Unfortunately I'm not aware of any specific place for that: I wrongly
> thought that you were involved in the development of the modem and you
> knew the chipset.

Thank you for thinking like that. However, I'm just a Linux lover and
a Microsoft Surface user.

> However, sometimes the name of the chipset is left in the firmware
> revision: you can try looking if there's any hint in the output of the
> device caps request. If it's a Qualcomm modem it should probably also
> support QMI-over-MBIM service, so maybe you can also try a few DMS
> requests (--dms-get-software-version, --dms-get-revision...).
>
> Sometimes also the USB descriptors can be useful.

According to your guides, I did get some useful information from my
Surface Go 3 modem. Finally, it was based on a Qualcomm chip, and
other Microsoft mobile broadband modems should be based on the
Qualcomm chip. The test results on my Surface Go 3 are below.

==== Start of test results ====
 $> lsusb
Bus 002 Device 004: ID 045e:09a5 Microsoft Corp. Surface

$> lsbusb -t
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
    |__ Port 1: Dev 5, If 0, Class=Hub, Driver=hub/4p, 5000M
        |__ Port 4: Dev 6, If 0, Class=Vendor Specific Class,
Driver=r8152, 5000M
    |__ Port 3: Dev 4, If 0, Class=Communications, Driver=cdc_mbim, 5000M
    |__ Port 3: Dev 4, If 1, Class=CDC Data, Driver=cdc_mbim, 5000M
    |__ Port 3: Dev 4, If 2, Class=Vendor Specific Class, Driver=, 5000M

$> qmicli --device=/dev/cdc-wdm3 --dms-get-manufacturer
[/dev/cdc-wdm3] Device manufacturer retrieved:
Manufacturer: 'QUALCOMM INCORPORATED'

$> qmicli --device=/dev/cdc-wdm3 --dms-get-revision
[/dev/cdc-wdm3] Device revision retrieved:
Revision: '2140-e88e4b-c8-00004.36  1  [May 17 2021 01:00:00]'

$> qmicli --device=/dev/cdc-wdm3 --dms-get-software-version
[/dev/cdc-wdm3] Software version: 655_GEN_PACK-1.362573.1.400078.2

$> qmicli --device=/dev/cdc-wdm3 --dms-get-band-capabilities
[/dev/cdc-wdm3] Device band capabilities retrieved:
Bands: 'wcdma-2100, wcdma-pcs-1900, wcdma-850-us, wcdma-800, wcdma-900'
LTE bands: '1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 19, 20, 25, 26, 28, 29,
30, 38, 39, 40, 41'
LTE bands (extended): '1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 19, 20, 25,
26, 28, 29, 30, 38, 39, 40, 41, 66'

$> qmicli --device=/dev/cdc-wdm3 --dms-get-capabilities
[/dev/cdc-wdm3] Device capabilities retrieved:
Max TX channel rate: '50000000'
Max RX channel rate: '100000000'
       Data Service: 'non-simultaneous-cs-ps'
                SIM: 'supported'
           Networks: 'umts, lte'
==== End of test results ====

Thank you for your help.

Best regards,
Seunghun

> Regards,
> Daniele
>