Hi folks, I noticed a regression introduced sometime after 4.19.4 in USB power management. I have a 2015 MacBook Pro. When I try to do a suspend or a suspend+hibernate, I get the following error messages trying to suspend usb2 and the suspend fails. This works fine in 4.19.4: Dec 22 13:50:36 eric-macbookpro kernel: Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. Dec 22 13:50:36 eric-macbookpro kernel: Suspending console(s) (use no_console_suspend to debug) Dec 22 13:50:36 eric-macbookpro kernel: dpm_run_callback(): usb_dev_freeze+0x0/0x10 returns -16 Dec 22 13:50:36 eric-macbookpro kernel: PM: Device usb2 failed to freeze async: error -16 Dec 22 13:50:38 eric-macbookpro systemd[1]: systemd-hybrid-sleep.service: Main process exited, code=exited, status=1/FAILURE Dec 22 13:50:38 eric-macbookpro systemd[1]: systemd-hybrid-sleep.service: Failed with result 'exit-code'. Dec 22 13:50:38 eric-macbookpro systemd[1]: Failed to start Hybrid Suspend+Hibernate. Dec 22 13:50:38 eric-macbookpro systemd[1]: Dependency failed for Hybrid Suspend+Hibernate. Dec 22 13:50:38 eric-macbookpro systemd[1]: hybrid-sleep.target: Job hybrid-sleep.target/start failed with result 'dependency'. Dec 22 13:50:38 eric-macbookpro systemd-logind[1573]: Operation 'sleep' finished. Dec 22 13:50:38 eric-macbookpro systemd[1]: Stopped target Sleep. The behavior exists in 4.19.8 and 4.19.11, the kernel versions I have upgraded to with Arch Linux, so the regression was introduced sometime between 4.19.4 and 4.19.8. Hibernate still works but when I resume from hibernate, there is a ksoftirqd and kworker thread/process together taking up 100% of one core. If I turn off auto power control for usb1 and usb2, the threads stop spinning. i.e., echo 'on' > '/sys/bus/usb/devices/usb1/power/control Any suggestions as to where this regression was introduced and what can be done to fix it? Thanks, Eric
