On Tue, Oct 17, 2023 at 02:23:05AM +0000, Li, Meng wrote: > I did some debugs on my side. > Firstly, the local_irq_disable_nort() function had been removed from latest RT kernel. What's in the RT kernel doesn't matter here, because the code you're patching belongs to the vanilla kernel. > Second, because of creating xhci-pci.c, the commit c548795abe0d("USB: add check to detect host controller hardware removal") is no longer useful. > Because the function usb_remove_hcd() is invoked from xhci_pci_remove() of file xhci-pci.c in advance. What about for non-xHCI controllers? > I am trying to fix this issue with getting register status directly without local_irq_disable(). Were you able to locate the original bug report? Alan Stern