+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? Thanks, -- heikki -- 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
