On Sat, Apr 02, 2022 at 06:18:26AM +0200, Petr Janecek wrote: > I've compared traces in linux to macos and windows, and > the only thing linux does that the others don't is something > like > > usb_get_string(dev, 0, 0xee, &buf, 1024) > > like it's getting the microsoft os descriptor. Exactly so. > And the apogee does not like it: it's the only get > descriptor string request with empty string response. When > the request is made the second time, it's the last request > before reset. That doesn't necessarily mean anything, of course. > This oddball request happens even with snd-usb-audio > disabled. And I'm totally unable to find where it comes > from, I have not enabled anything like USB_GADGET. > How to get rid of it? It might not come from a kernel driver at all; it might come from a user program via usbfs. Try turning on usbfs snooping before you plug in the device: echo 1 >/sys/module/usbcore/parameters/usbfs_snoop and see what shows up in the kernel log. Alan Stern
