Re: [PATCH] USB: Add quirk for WORLDE easykey.25 MIDI keyboard

[Oliver Neukum <oneukum@suse.com>]

Am Montag, den 23.01.2017, 19:36 +0100 schrieb Lukáš Lalinský:
> On Sat, Jan 21, 2017 at 10:08 AM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > 
> > Always use scripts/get_maintainer.pl to determine who to send
> > patches
> > to, and what mailing list.  You forgot linux-usb@vger, which I've
> > now
> > added...
> 
> I'm sorry about that. I actually did use scripts/get_maintainer.pl,
> but it only returned your email address and I added linux-kernel@vger
> myself. I guess I ran it with wrong options.
> 
> > 
> > That's odd, how does other operating systems handle this device?
> 
> I'm not sure how realistic this test is, but I ran a Wireshark
> capture
> from Windows 8.1 VM and it seems that for this particular device,
> Windows doesn't try to set the current configuration (since there is
> only one) and it does not even attempt to get the configuration
> string
> descriptor. I'm not sure if Windows does this in general, but it
> seems
> to work around the problem for this device by not caring about the
> configuration string descriptor in the first place.
> 
> I have uploaded both captures here -
> https://gist.github.com/lalinsky/83148a827d5cd43e79e377d8e1b5ed0d

Indeed it is does not set a configuration. Either the capture
is incomplete or device and host violate the standard. A device
may be left unconfigured. We need to read the descriptors even if we
see only one configuration to get the power budgeting right.

Does the device work without any .ini file?

	Regards
		Oliver