On Wed, Dec 18, 2024 at 01:02:39PM +0100, Johan Hovold wrote: > On Wed, Dec 18, 2024 at 05:08:30PM +0530, Manivannan Sadhasivam wrote: > > On Wed, Dec 18, 2024 at 09:40:45AM +0100, Johan Hovold wrote: > > > > I've tracked down the hang to a deadlock on the parent device lock. > > > > > > Driver core takes the parent device lock before calling shutdown(), and > > > then mhi_pci_shutdown() waits indefinitely for the recovery thread to > > > finish. > > > Thanks for tracking the deadlock. I think we should use pci_try_reset_function() > > instead of pci_reset_function() in mhi_pci_recovery_work(). > > > > If the pci_dev_lock() is already taken, it will return with -EAGAIN and we do > > not need to worry in that case since the host is going to be powered off anyway > > (and so the device). > > That may work. But note that I've now also seen this deadlock during > suspend (i.e. when the device is not going away). The > pci_try_reset_function() should avoid the deadlock here too, but we'll > end up in funny state. > Hopefully, recovery_work() started by mhi_pci_runtime_resume() would be able to reset the device. > Now I'd also like to know why I'm suddenly seeing these runtime PM > resume errors of this modem. Haven't seen them before 6.13-rc, and I'm > not sure that it's really the firmware that is crashing left and right > all of a sudden. > Yeah, that's worth the effort. I'll go ahead with the patch since the issue is present anyway. - Mani -- மணிவண்ணன் சதாசிவம்
