FixedSpeed registry setting

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BruteForce

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Dec 1, 2006, 5:38:33 AM12/1/06

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This is a new registry setting that will be available in the
forthcoming 5.11 release of the ubCore drivers.

This setting can instruct the Class Driver to not perform the complete
path speed detection algorithm, but instead assume that all nodes
operate at the same (fixed) speed. This can be used in custom and
controlled bus configurations, where you know beforehand that all nodes
operate at the same speed.

Path speed detection is an activity that is performed in the bus-reset
handler in the Class Driver and it involves doing remote PHY register
reads. When the bus is loaded with isochronous traffic then this
activity might take several milliseconds to complete. When the bus
configuration is tightly controlled you can instruct the Class Driver
to assume a fixed speed for all nodes, thus eliminating all remote PHY
packets and achieving the fastest possible processing from the Class
Driver bus-reset handler.

Using the FixedSpeed setting in conjunction with the
DisablePnPEnumeration setting on all PCs on the bus currently
eliminates ALL post-BusReset traffic from the ubCore drivers.

The setting is available from Class Driver version 5.1.66.0 or later.
It's value can be controlled using the UBTWEAK utility (version 5.1.0.1
or later) which is included in ubCorePro 5.11.