Am Dienstag, den 24.01.2017, 08:37 +0100 schrieb Lukáš Lalinský: > On Tue, Jan 24, 2017 at 8:32 AM, Oliver Neukum <oneukum@xxxxxxxx> > wrote: > > > > Am Montag, den 23.01.2017, 19:36 +0100 schrieb Lukáš Lalinský: > > > > > > 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 You can leave a device unconfigured. In that case it stays in the addressed state, where its power draw is strictly limited. That is exactly what the kernel does when it is confronted with a device that would overdraw the power budget. > 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. No, it is not. Or rather it should not be. Can you please recheck that you are capturing the whole exchange? > > 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 True. > descriptor is probably only useful if you need to print the > configuration details somewhere. Also true. > > > > Does the device work without any .ini file? > > Yes. It's a standard MIDI device, no configuration is required. So Windows by default does not read string descriptors. That is worth a thought, but we need to check. Yet I am not sure how useful that is. The first lsusb would crash the device. We'd need a quirk anyway. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
