Commits
Simon Arlott committed fca5430d48d
USB: ftdi_sio: fix status line change handling for TIOCMIWAIT and TIOCGICOUNT Handling of TIOCMIWAIT was changed by commit 1d749f9afa657f6ee9336b2bc1fcd750a647d157 USB: ftdi_sio.c: Use ftdi async_icount structure for TIOCMIWAIT, as in other drivers FTDI_STATUS_B0_MASK does not indicate the changed modem status lines, it indicates the value of the current modem status lines. An xor is still required to determine which lines have changed. The count was only being incremented if the line was high. The only reason TIOCMIWAIT still worked was because the status packet is repeated every 1ms, so the count was always changing. The wakeup itself still ran based on the status lines changing. This change fixes handling of updates to the modem status lines and allows multiple processes to use TIOCMIWAIT concurrently. Tested with two processes waiting on different status lines being toggled independently. Signed-off-by: Simon Arlott <simon@fire.lp0.eu> Cc: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>