Question on ----wda-set-data-format -> ul_protocol/dl_protocol

[Aleksander Morgado]

Hey,

> on
>
> https://lists.freedesktop.org/archives/libqmi-devel/2018-July/002935.html
>
> there is an (old? obsolete?) example for --wda-set-data-format:
>
> qmicli -p -d /dev/cdc-wdm0 --wda-set-data-format="link-layer-protocol=raw-ip,ul-protocol=qmap,dl-protocol=qmap,dl-max-datagrams=32,dl-datagram-max-size=32768,ep-type=hsusb,ep-iface-number=8" --client-cid=$wda_cid --client-no-release-cid
>
> There ul-protocol and dl-protocol are filled with value "qmap".
>
> Looking at this page
>
> https://lazka.github.io/pgi-docs/Qmi-1.0/enums.html#Qmi.WdaDataAggregationProtocol
>
> there are meanwhile much more values for it like
>
> QMAPV2
>
> QMAPV3
>
> QMAPV4
>
> QMAPV5
>
> There is not really a description for it on this page. I tried, I can use e.g. "qmapv5" with --wda-set-data-format.
>
> Then there is this page:
>
> https://docs.kernel.org/networking/device_drivers/cellular/qualcomm/rmnet.html
>
> It describes the raw packets for v1 to v5.
>
> But now I still have not more knowledge, in what situation to use each version.
>
> Or if QMAPV5 shall always be used (with latest kernel), because it makes all previous version obsolete.
>
> Or are certain values used for certain use cases? Is there perhaps a more detailed description?
>

The specific QMAP version flag to use depends on each modem. Some
devices will require v5, some others v4. I don't think there is a way
to know beforehand which one is required in each device. What
ModemManager does for example is to try combinations one by one, see
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/blob/main/src/mm-port-qmi.c#L1240

-- 
Aleksander