Re: [PATCH v5] USB: core: skip unconfiguration if device doesn't support it

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, May 13, 2022 at 10:09:26AM -0400, Alan Stern wrote:
> On Fri, May 13, 2022 at 11:50:26AM +0200, Jose Ignacio Tornos Martinez wrote:
> > Ok, I will try to identify the "bad" devices in some way.
> > 
> > Thanks
> > 
> > José Ignacio
> > 
> > 
> > On Thu, May 12, 2022 at 1:48 PM Greg KH <gregkh@linuxfoundation.org> wrote:
> > >
> > > I'll drop this for now as there are no in-kernel users for this quirk
> > > yet.  When there is a need for one, please resubmit it.
> 
> Hold on; Greg's comment doesn't seem fair.  There are no in-kernel 
> users for this quirk because it is meant to be a user API.  (Just as 
> there are no in-kernel users for read(2) -- it is there so that 
> userspace can call it).

True, but the kernel calls read(2) itself as well in places, it just
looks a bit different, kernel_read_file()  :)

> Jose does have users for the new quirk: Anybody with one of the bad 
> Bluetooth CSR knockoff chips.  Now I agree; it would be great if there 
> was some way to identify them automatically.  But if that's not 
> possible, the only alternative is to allow userspace to set the quirk 
> flag whenever it knows the quirk is needed.

Is that the case here that we know how to identify this?  I thought
Marcel said something else was happening here.

If the bluetooth developers/maintainers say this is needed for some
devices to work properly and they will be handled in userspace somehow
through a udev rule or the like, I will gladly add this.  But I thought
this thread died out as it was determined that this wasn't needed at
this point in time which is why I dropped it.

thanks,

greg k-h