• Johan Hovold's avatar
    USB: serial: cp210x: suppress modem-control errors · 5951b850
    Johan Hovold authored
    
    
    The CP210X_SET_MHS request cannot be used to control RTS when hardware
    flow control (auto-RTS) is enabled and instead returns an error which is
    currently logged as:
    
    	cp210x ttyUSB0: failed set request 0x7 status: -32
    
    when opening and closing a port (and on TIOCMSET requests).
    
    Add a crtscts flag to keep track of the hardware flow-control setting
    and use it to suppress any request to change RTS when auto-RTS is
    enabled.
    
    Note that RTS is still deasserted when disabling the UART as part of
    close.
    Reported-by: default avatarPho Tran <pho.tran@silabs.com>
    Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
    5951b850