[systemd-devel] WebUSB

[Bjørn Mork]

Lars Knudsen <larsgk at gmail.com> writes:

> configured with [0]CDC INT, [1]CDC BULK and [2]WebUSB CDC/BULK) would:
>
> 1) not be considered a modem (it would not make sense to do a modem
> including webusb headers - in the same device mode at least)
> 2) provide standard /dev/ttyUSBx serial functionality on the standard CDC
> endpoints (e.g. interface 1 above)
> 3) provide full user access to the WebUSB CDC/BULK interface (2 above)
>
> What I was asking before is for an example header/configuration descriptors
> where MM would *not* pick up the CDC interface but the system still
> creating a /dev/ttyUSBx device (or ttyACMx - which it's called when MM is
> installed) - without creating blacklisting rules specifically for e.g.
> *that* VID/PID combo.
> When I was experimenting the last few days - this did not seem possible.  I
> had to completely wipe any indication of this device being CDC before MM
> stopped claiming it.  Surely, MM should not pick it up if the device
> indicates it doesn't have call functionality?

This is hard to decipher.

I tend to interprete "a CDC interface" as a "Communications Class
Interface" as defined by "Universal Serial Bus Class Definitions for
Communications Devices".  But this makes no sense in the context you are
using it, so I guess I am misunderstanding?

I don't think any current kernel driver will create /dev/ttyUSBx devices
for any type of CDC function, so that makes no sense either.

/dev/ttyACMx devices are created by the CDC ACM driver, and has nothing
to do with MM being installed or not.

In short: I don't understand anything of the above. I believe the
requested descriptor samples would clear up some of this.  As would some
references to the CDC spec if you are going to continue using parts of
if to describe the device.


Bjørn