Hi Mathias, Here's an interesting development: as a result of a related thread on linux-media, I came across a patch they are distributing in openelec: https://github.com/OpenELEC/OpenELEC.tv/commit/b636927dec20652ff020e54ed7838a2e9be51e03 Now I'm not saying that reverting the commit in question is the "right" thing to do, but I applied this patch and for the first time in 100+ tests it started to work (i.e. I'm not seeing the XHCI hcd tear down all the attached devices). Given what I've seen of the bug I cannot really explain why the scatter gather list sizes would have any bearing on TRBs for USB control messages to be added to the queue. Perhaps we're hitting the upper bound of the list? Any further speculation on my part would just make me look clueless... It would be great if you could offer any insight as to why the patch in question could be responsible for the behavior we're seeing. I would really rather not just blindly check this patch into my local tree and declare "victory" without understanding the underlying issue and whether it's likely to cause other problems. Devin -- Devin J. Heitmueller - Kernel Labs http://www.kernellabs.com -- 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