usb-gadget: dynamic reconfiguration

usb-gadget: dynamic reconfiguration

[Shantur Rathore]

Hi all,

I am trying to figure out if it's possible to reconfigure a usb-gadget
when it's live.
The idea is to create a gadget with 1 function - lets say a serial gadget.

Upon communication with the host, the host could specify (via Serial
communication) which is the next gadget it needs for example a mass
storage or ecm and the next gadget can be added to the configuration.

For now this only works if the gadget is disconnected and reconnected
to the UDC.

I want to understand if it is technically possible to add more
functions to a live config without affecting existing functions.

Kind regards,
Shantur

Re: usb-gadget: dynamic reconfiguration

[Greg KH]

On Mon, Nov 08, 2021 at 12:54:37PM +0000, Shantur Rathore wrote:
> Hi all,
> 
> I am trying to figure out if it's possible to reconfigure a usb-gadget
> when it's live.
> The idea is to create a gadget with 1 function - lets say a serial gadget.
> 
> Upon communication with the host, the host could specify (via Serial
> communication) which is the next gadget it needs for example a mass
> storage or ecm and the next gadget can be added to the configuration.
> 
> For now this only works if the gadget is disconnected and reconnected
> to the UDC.
> 
> I want to understand if it is technically possible to add more
> functions to a live config without affecting existing functions.

The USB standard does not allow for this type of thing, sorry.  So this
really isn't anything you could do on the gadget side and expect the
host side to notice it.

thanks,

greg k-h

Re: usb-gadget: dynamic reconfiguration

[Felipe Balbi]

Hi,

Shantur Rathore <i@shantur.com> writes:
> Hi all,
>
> I am trying to figure out if it's possible to reconfigure a usb-gadget
> when it's live.
> The idea is to create a gadget with 1 function - lets say a serial gadget.
>
> Upon communication with the host, the host could specify (via Serial
> communication) which is the next gadget it needs for example a mass
> storage or ecm and the next gadget can be added to the configuration.
>
> For now this only works if the gadget is disconnected and reconnected
> to the UDC.
>
> I want to understand if it is technically possible to add more
> functions to a live config without affecting existing functions.

the only thing you can do is upon a certain command, logically
disconnect from the bus and connect again as a new device.

-- 
balbi

Re: usb-gadget: dynamic reconfiguration

[Shantur Rathore]

On Mon, Nov 8, 2021 at 1:08 PM Felipe Balbi <balbi@kernel.org> wrote:
>
>
> Hi,
>
> Shantur Rathore <i@shantur.com> writes:
> > Hi all,
> >
> > I am trying to figure out if it's possible to reconfigure a usb-gadget
> > when it's live.
> > The idea is to create a gadget with 1 function - lets say a serial gadget.
> >
> > Upon communication with the host, the host could specify (via Serial
> > communication) which is the next gadget it needs for example a mass
> > storage or ecm and the next gadget can be added to the configuration.
> >
> > For now this only works if the gadget is disconnected and reconnected
> > to the UDC.
> >
> > I want to understand if it is technically possible to add more
> > functions to a live config without affecting existing functions.
>
> the only thing you can do is upon a certain command, logically
> disconnect from the bus and connect again as a new device.

thanks guys, always helpful.

>
> --
> balbi