Hi, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes: > On Tue, 11 Jun 2019, Felipe Balbi wrote: > >> >> >> > So for "severe" issues, yes, we should do this, but perhaps not for all >> >> >> > of the "normal" things we see when a device is yanked out of the system >> >> >> > and the like. >> >> >> >> >> >> Then what counts as a "severe" issue? Anything besides enumeration >> >> >> failure? >> >> > >> >> > Not that I can think of at the moment, other than the other recently >> >> > added KOBJ_CHANGE issue. I'm sure we have other "hard failure" issues >> >> > in the USB stack that people will want exposed over time. >> >> >> >> From an XHCI standpoint, Transaction Errors might be one thing. They >> >> happen rarely and are a strong indication that the bus itself is >> >> bad. Either bad cable, misbehaving PHYs, improper power management, etc. >> > >> > Don't you also get transaction errors if the user unplugs a device in >> > the middle of a transfer? That's not the sort of thing we want to sent >> > notifications about. >> >> Mathias, do we get Transaction Error if user removes cable during a >> transfer? I thought we would just get Port Status Change with CC bit >> cleared, no? > > Even if xHCI doesn't give Transaction Errors when a cable is unplugged > during a transfer, other host controllers do. Sometimes quite a lot -- > they continue to occur until the kernel polls the parent hub's > interrupt ep and learns that the port is disconnected, which can take > up to 250 ms. my comment was specific about XHCI. It even started with "From an XHCI standpoint" :-) -- balbi
