Monty’s new EHCI scheduler
Linux’s EHCI scheduler has some known problems with bandwidth allocation that may prevent you from using isochronous devices (USB audio, for example).
Christopher Montgomery (AKA, Monty) is trying to fix these problems and has made available a patch which fixes some issues he got with a eMagic device.
I gave his patch a try and didn’t get any problem so far, but as I don’t have isochronous devices my tests were very limited (I just tried to stress it a bit by doing some full- and high-speed transfers in parallel).
But the good news is that Monty’s patch has fixed a problem a Mandriva contributer was facing with his Audigy 2 device last week.
Then, if you’re getting errors like ‘cannot submit datapipe‘ when trying to use high-speed USB devices in Linux, it might be a good idea to try Monty’s patch.
You’ll find it here, along with a nice high-level description.