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? Thanks & best regards, 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
