On Mon, Jan 26, 2015 at 4:37 AM, Devin Heitmueller <dheitmueller@xxxxxxxxxxxxxx> wrote: > 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. Just as another point of data... I applied the patch to Mathias for-usb-next-test branch and was able to record video and audio through the Live2 for the first time using the xhci stack. Attempting to record a second video resulted in mythffmpeg returning: [alsa @ 0xbf6560] cannot open audio device plughw:CARD=Cx231xxAudio,DEV=0 (Device or resource busy) plughw:CARD=Cx231xxAudio,DEV=0: Input/output error I also get this error on the older hardware running ehci, although it can be recovered by removing and re-inserting the Live2. Attempting to do this under xhci resulted in usb locking up somehow, lsusb never returned. syslog file at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1412121/+attachment/4305645/+files/2015-01-26-syslog-14.10-3.19rc5akg0.1.log Thanks again to you both, Alistair -- 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
