On Sat, Jul 18, 2020 at 04:49:41PM +0200, Achim Dahlhoff wrote: > Reproduceable hung-task in snd_usb_pcm or usb-core in VM with Behringer device. > > Hello maintainers of usb, > > I found a reproduceable hung-task problem when trying to use Behringer > "Uphoria" audio devices inside VMware workstation, on Debian-SID with > kernel 5.7 or with 5.8-rc5 . Kernel-trace and USB IDs are included. > > Am I right to post here? Yes. > The problem occurs every time when accessing the devices. > The problem does NOT occur with: > - another sound device (griffin) > - on native Linux on another machine What about when you use the problematic machine with native Linux? That's really the most important case. > I cannot tell if it is a bug with VMware, the Behringer audio devices, > or if this might point to a bug in snd_usb_pcm. If the device works on the same machine under native Linux then most likely it is a problem in VMware. If it doesn't, the failure symptoms (a hang inside usb_kill_urb) indicate a problem in the USB host controller hardware or driver, not in snd_usb_pcm or the audio device. > If you have an idea what to try I can apply patches, rebuild kernel > and try if an improvement works. Try booting from a "Live" distribution and see what happens, if you don't want to install Linux on the test machine. Alan Stern
