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

[LukÃÅ LalinskÃ]

On Tue, Jan 24, 2017 at 8:37 AM, LukÃÅ Lalinskà <lukas@xxxxxxxxxx> wrote:
> On Tue, Jan 24, 2017 at 8:32 AM, Oliver Neukum <oneukum@xxxxxxxx> wrote:
>> Am Montag, den 23.01.2017, 19:36 +0100 schrieb LukÃÅ LalinskÃ:
>>> 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.
>
> Is this may or may not? I'm not familiar with USB, so I assumed if
> there is only one configuration and there is always one active, it
> does not need to be set explicitly because the correct one is already
> active.
>
>> We need to read the descriptors even if we
>> see only one configuration to get the power budgeting right.
>
> Aren't those in the CONFIGURATION descriptors? Reading the STRING
> descriptor is probably only useful if you need to print the
> configuration details somewhere.

I re-ran the capture on a Windows 7 host. The previous capture was
missing data, probably due to interactions of the Linux host and
Windows VM.

https://gist.github.com/lalinsky/2ec7d74b049b448b1f7032d8861ca4a2

It does set the configuration, but does not request the string descriptor.

Lukas