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    EHCI: force high-speed devices to run at full speed · 57e06c11
    Alan Stern 提交于
    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: NAlan Stern <stern@rowland.harvard.edu>
    Cc: David Brownell <dbrownell@users.sourceforge.net>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
    57e06c11
ehci-hub.c 20.0 KB