On Friday 06 October 2006 9:15 pm, Christopher "Monty" Montgomery wrote: > On 10/6/06, David Brownell <[EMAIL PROTECTED]> wrote: > > Not a good analogy. More accurate would be a jigsaw puzzle ... because > > you can pull a piece out of the middle, and then safely put it back in > > the same place. > > I chose my analogy carefully. If we were doing better than we're > doing right now, it would be like a jigsaw puzzle. That's the next > step. Right now, it is Jenga.
"Right now" == what's in 2.6.19-rc1, and that's like the jigsaw. > The optimal situation is tetris with entirely square blocks. I'm not sure I'd agree; certainly I chose my analogy carefully too. Admittedly I wasn't aiming to capture the dynamic aspects of bandwidth allocation, but just the reality that once you have a schedule budgeted for all periodic endpoints, there's nothing to keep you from taking those endpoints out and putting them back any number of times without re-budgeting. EHCI can't really do "square tetris". It's not a video game. ;) > That's > two steps away, but EHCI makes it difficult. Mark the QH idle, wait > for the HC to handshake, alter, reactivate, repeat. There will need > to be minor cleverness to prevent it from taking bloody forever while > holding a spinlock. Two stage commit with budget locking seperated > out... How long it takes is orthogonal. So long as the "reactivate" can see the old schedule position, and verify it, that's sufficient to make sure the jigsaw puzzle goes back together in the same way. > > You're deeply mis-understanding something if you think the reservation > > is associated with an URB. > > It was, effectively, up until now. The only reservation of a slot was > the presence of a URB in that slot in the schedule. The reservation is associated with that endpoint being active. Activity is defined by the endpoint's URB queue being non-empty... not a specific URB. - Dave ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
