Hi Stephan, On Mon, 11 Oct 2021 at 16:51, Stephan Gerhold <stephan@xxxxxxxxxxx> wrote: > > Like in the RFC version [1], the driver does not currently use the link > > management of the WWAN subsystem. Instead, it simply exposes one network > > interface for each of the up to 8 channels. > > > > This setup works out of the box with all available open-source userspace > > WWAN implementations, especially ModemManager (no changes needed). > > oFono works too although it requires minor changes to support WWAN control > > ports (/dev/wwan0qmi0) which are independent of BAM-DMUX (already provided > > by the "rpmsg_wwan_ctrl" driver). > > It was easy to support because the setup is very similar to ones already > > supported for USB modems. Some of them provide multiple network interfaces > > and ModemManager can bundle them together to a single modem. > > > > I believe it is best to keep this setup as-is for now and not add even > > more complexity to userspace with another setup that works only in this > > particular configuration. I will reply to this patch separately to explain > > that a bit more clearly. This patch is already long enough as-is. :) > > > > [1]: https://lore.kernel.org/netdev/20210719145317.79692-5-stephan@xxxxxxxxxxx/ > > > > The main goal of the WWAN link management is to make the multiplexing > setup transparent to userspace. Unfortunately it's still unclear to me > how or even if this can be achieved for the many different different > setups that exist for Qualcomm modems. To show that more clearly I'll > "briefly" list the various currently supported setups in ModemManager > (there might be even more that I am not even aware of). The goal is also to have a common hierarchy, with the network link being a child of the WWAN device, as for the control ports. Making it easier for the user side to find the relation between all these devices. Moreover, it allows having a common set of attributes, like the LINK ID, and possibly new ones in the future. I mean it's probably fine if you create a static set of network devices and do not support dynamic link creation, but I think they should be created in some way via the WWAN subsystem, and get the same attributes (link id), we can have special meaning link ids (-1) for e.g. non context specific netdevs (e.g. for rmnet/qmap transport iface). Regards, Loic
