tree ef69ed0b3c7f5805ac80eba1d9b01ccd6be2046d
parent ed3d6d0ac036bcff6e4649a6f8fb987bb4e34444
author Alan Stern <stern@rowland.harvard.edu> 1474035866 -0400
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1474036181 +0200

USB: change bInterval default to 10 ms

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: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Wade Berrier <wberrier@gmail.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>