On Thu, Jun 25, 2020, at 11:17 AM, Mark Deneen wrote:
> On Thu, Jun 25, 2020 at 12:13 PM Sid Spry <sid@xxxxxxx> wrote:
> >
> > On Thu, Jun 25, 2020, at 9:18 AM, Mark Deneen wrote:
> > > Am I doing something incorrectly? What can I do to debug this further?
> > >
> >
> > On my device it's impossible to remove anything from the configuration once
> > added. Are you sure it is expected that the gadget can be reconfigured after
> > UDC binding and then unbinding? (This is a general question to the list as
> > well, I'd like an answer to your original post also.)
> >
> > My workaround is creating a new gadget and binding the UDC to that instead.
> > Or just rebooting.
>
> I was able to remove the gadget configuration on Jetson Nano using
> their BSP Kernel (tegra) without an oops, but I have no idea how much
> that kernel differs from mainline.
>
> If it is not possible, surely crashing is not the desirable behavior!
>
> What happens on your device if you attempt to remove the configuration?
>
I get "Device or resource busy" even after ensuring I've unlinked the function
from the configs directory. More recently after putting a FunctionFS filesystem
in the gadget I am now unable to unbind the UDC, and dmesg shows that
unbinding seems to erroneously invoke the binding code with an invalid
argument ('').
I've also been able to unbind the UDC but then been unable to rebind it to
anything else but that is sporadic. More typically if I just use premade functions
I can rebind as much as I want, just not change gadgets after the first binding.
>From an expected-functionality standpoint it is fairly obvious that what you (and
I) are trying to do should be supported, but realistically it seems like only setup
was tested in any detail as devices that reconfigure themselves are vanishingly
rare.
