This updates the EHCI driver by adding an improved scheduler for the
transaction translators, found in USB 2.0 hubs and used for low and
full speed devices.
- adds periodic_tt_usecs() and some helper functions, which does
the same thing that "periodic_usecs" does, except on the other
side of the TT, i.e. it calculates the low/fullspeed bandwidth
usage instead of highspeed.
- adds a tt_available() function which is the new implementation
of what tt_no_collision() does ... while tt_no_collision() ensures
that each TT handles only 1 periodic transfer at a time (a very
pessimistic approach) this version instead tracks bandwidth and
allows each TT to handle as many transfers as will fit on each TT's
downstream bus (closer to best-case).
The new scheduler is selected by a config option, marked as EXPERIMENTAL
so it can be tested (and more broadly reviewed) for a while until it
seems safe to remove the original scheduler.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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