• Russell King's avatar
    [SERIAL] Clean up and fix tty transmission start/stoping · b129a8cc
    Russell King authored
    The start_tx and stop_tx methods were passed a flag to indicate
    whether the start/stop was from the tty start/stop callbacks, and
    some drivers used this flag to decide whether to ask the UART to
    immediately stop transmission (where the UART supports such a
    feature.)
    
    There are other cases when we wish this to occur - when CTS is
    lowered, or if we change from soft to hard flow control and CTS
    is inactive.  In these cases, this flag was false, and we would
    allow the transmitter to drain before stopping.
    
    There is really only one case where we want to let the transmitter
    drain before disabling, and that's when we run out of characters
    to send.
    
    Hence, re-jig the start_tx and stop_tx methods to eliminate this
    flag, and introduce new functions for the special "disable and
    allow transmitter to drain" case.
    Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
    b129a8cc
sunzilog.c 44 KB