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Revision a145ea51


Added by aliguori over 12 years ago

uhci: Change default transaction lifetime to 32 frames (Max Krasnyansky)

Transaction lifetime was originally set to 10 frames. That was an arbitrary
number I picked without much thinking :).
I'm changing that to 32 frames because things like interrupt transfers
and such are scheduled at that rate. It seems like 1/32 is accepted as
lowest supported rate. OHCI, for example, defines exactly 32 interrupt

While testing USB webcam under XP I noticed that interrupt transactions were
being canceled and then resubmitted on a regular basis, which works but is a
waste of CPU cycles. This change fixes that.
All other devices I have are not affected.

Signed-off-by: Max Krasnyansky <>
Signed-off-by: Anthony Liguori <>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5199 c046a42c-6fe2-441c-8c8c-71466251a162


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