On Mon, 2018-06-25 at 13:11 +0300, Heikki Krogerus wrote: > +Mika > > On Fri, Jun 22, 2018 at 10:12:10AM +0200, Timur Krist?f wrote: > > Hi, > > > > I have a Dell XPS 13 9370, which has just Type-C ports. Currently > > running kernel 4.17.2. I found that plugging in a powered USB hub > > into > > the Type-C port does not work. > > > > Please let me know if this isn't the correct place to report this > > problem. Not sure if this is a Dell-specific issue or a Linux- > > specific > > issue, so I'm also CCing Mario from Dell. > > > > The following test cases were tried: > > > > 1. When I plug in the hub to the laptop, and then plug in the > > peripherals, it works as expected. (This is OK.) > > > > 2. But when I plug peripherals into the hub, and then plug it into > > the > > laptop, it takes at least 10-30 seconds to detect them. (Until then > > they don't show up in lsusb.) > > > > 3. If the hub is powered and power is connected to the hub before > > plugging it in, it is not detected at all. Sometimes it is detected > > after being plugged in for a very long time, but not always. > > > > I tried with various different configurations: > > > > A. Dell USB Type-C to Type-A adapter with a Speedlink USB 2.0 hub. > > > > B. Same Dell C-to-A adapter with the built-in USB 2.0 hub of a Dell > > P2414H monitor. > > > > C. Qoltec USB Type-C to USB 3.0 hub > > > > All of these exhibited the same behaviour. When the hub was powered > > before plugging it in, then they were not recognized at all, when > > unpowered they were recognized in ~ 30 seconds (which is still too > > long > > though). > > > > Note that the USB 2.0 hubs both worked correctly with other > > machines > > which just had a USB-A port. When plugged into a USB-A port, all > > the > > connected peripherals were immediately detected as soon as the hub > > was > > plugged in. > > > > What might be the issue here? How can I help debug this further? > > This could be a problem with the Thunderbolt controller. Mika, do you > know if there are any known problems when using self powered USB > hubs? > The issue also happens with the non-Thunderbolt USB Type-C port, at least on this laptop. Tim -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
