This is very helpful debugging USB issues.
Reviewed-by: NFabio Estevam <festevam@gmail.com>
Signed-off-by: NAndreas Müller <schnitzeltony@gmail.com>
Signed-off-by: NOtavio Salvador <otavio@ossystems.com.br>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>