Hi Alan, Thanks for taking the time to respond. On Thu, Feb 6, 2014 at 5:08 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > Is it possible to get any debugging information from the machines in > the field? At this point all I know is the usb_submit_urb() is returning -EBIGF. In the 3.7 ehci_hcd driver that can come from one of three places and I'm in the process of deploying some additional logging so at least I know which of those three is causing it. I do know that when it occurs, it's not necessarily at the start of streaming (i.e. it's not some sort of initial bandwidth reservation issue). I see it happening when the URBs are being actively serviced by the completion handler and resubmitted. >> I know this is an atypical thing to consider since most devs work on >> the trunk, but can anybody give me a feel for how much breakage is >> likely to occur If I move the tree between those two revs? Have there >> been a ton of changes to common frameworks in the kernel that >> drivers/usb relies on? >> >> Suggestions welcome. > > That's a pretty hard question to answer. Probably the best way to find > out is try it and see what breaks. It may be easier to back-port just > the EHCI driver family and not the whole stack. Yeah, I'll take a crack at it. Figured I would ask to see if anybody would come out and say "don't even try it - we know it to be a lost cause." > I can point out that in the last one or two kernel releases there were > significant changes to the snd-usb-audio driver that affect the way it > interacts with ehci-hcd. Just to make your life more difficult... Supposedly they never had this issue in 2.6.33, so presumably it's some sort of regression in either the EHCI driver or snd-usb-audio between 2.6.33 and 3.7. That said, I'm hoping it's something already fixed in 3.13 and I just need to find the right change to backport. I know the ISO_ASAP behavior changed, but aside from that do you see any reason that I wouldn't be able to backport the entire snd-usb-audio driver from 3.13 (leaving the ehci driver at the 3.7 level)? Cheers, 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
