tree 4a4baca40490df08704271a6c39b0fa4a59edc95
parent be475d9027a07069407a19980d1a4fcb7b18b23c
author Alan Stern <stern@rowland.harvard.edu> 1243026153 -0400
committer Greg Kroah-Hartman <gregkh@suse.de> 1245127486 -0700

USB: EHCI: stagger frames for interrupt transfers

This patch (as1243) tries to improve ehci-hcd's scheduling of
interrupt transfers.  Instead of trying to cram all transfers with the
same period into the same frame, the new code will spread the
transfers out among lots of different frames.  This should reduce the
periodic schedule load in any one frame -- some host controllers have
trouble when there's too much work to do.

A more thorough approach would stagger the uframe values as well.  But
this is enough to make a big improvement.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Dwayne Fontenot <dwayne.fontenot@att.net>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>