• Alan Stern's avatar
    USB: change bInterval default to 10 ms · cfcbd5b8
    Alan Stern authored
    commit 08c5cd37 upstream.
    
    Some full-speed mceusb infrared transceivers contain invalid endpoint
    descriptors for their interrupt endpoints, with bInterval set to 0.
    In the past they have worked out okay with the mceusb driver, because
    the driver sets the bInterval field in the descriptor to 1,
    overwriting whatever value may have been there before.  However, this
    approach was never sanctioned by the USB core, and in fact it does not
    work with xHCI controllers, because they use the bInterval value that
    was present when the configuration was installed.
    
    Currently usbcore uses 32 ms as the default interval if the value in
    the endpoint descriptor is invalid.  It turns out that these IR
    transceivers don't work properly unless the interval is set to 10 ms
    or below.  To work around this mceusb problem, this patch changes the
    endpoint-descriptor parsing routine, making the default interval value
    be 10 ms rather than 32 ms.
    Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
    Tested-by: default avatarWade Berrier <wberrier@gmail.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    cfcbd5b8
config.c 26.3 KB