EHCI: force high-speed devices to run at full speed
This patch (as710) adds a sysfs class-device attribute file named "companion" for EHCI controllers. The file contains a list of port numbers that are dedicated to the companion controller; by writing a port number to the file the user can force a high-speed device attached directly to the computer to run at full speed. (As far as I know it is not possible to do this for a device attached to an external hub.) A port is removed from the file by writing the negative of its port number. Several users have asked for this facility and it seems like a useful thing to have. Every now and then one runs across a device which behaves much better at full speed than at high speed. Signed-off-by:Alan Stern <stern@rowland.harvard.edu> Cc: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by:
Greg Kroah-Hartman <gregkh@suse.de>
parent
625b5c9a
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