Hi Dirk, Thanks for testing that.
On Sat, Aug 29, 2020 at 11:04:43AM +0200, Dirk Kostrewa wrote: > Hi Salvatore, > > I have enabled the verbose debugging mode on the command line and have > appended the first 5000 lines of the dmesg output to this e-mail, running > the current kernel from the Buster backports with the two kworker processes > with high CPU load present. > > After that, I have applied your patch to this kernel and rebooted with the > patched kernel: > > 5.7.0-0.bpo.2-amd64 #1 SMP Debian 5.7.10-1~bpo10+1a~test (2020-08-28) x86_64 > GNU/Linux > > With your patch applied, the two kworker processes with high CPU load > completely disappeared! Unfortunately I suspect this indicates either a HW fault or a HW design error as stated in the found kernel-thread which was just uncovered by the mentioned kernel fix (which we temporarily reverted with the patch). I can try to ask Alan Stern. There might be a workaround workarble for you, the issue should disapear if you prevent the system to automatically try to suspend usb2 root hub (but you have the same on usb1 root hub). # echo on >/sys/bus/usb/devices/usb2/power/control will do that for the usb2 root hub. Regards, Salvatore
