Commits
Jarkko Huijts committed 6f602912c9d
usb: serial: ftdi_sio: Add missing chars_in_buffer function The driver does not wait until the hardware buffer (for data from the PC to the UART line) is drained when tcdrain or close is called in an application. Solution: Implement a chars_in_buffer function that checks both the software and hardware buffer. If the TEMT (TX empty) bit of the line status register indicates the hw buffer is not empty, let the function return at least 1. This has been verified to work correctly with an FT232RL. The check on the hw buffer can not be done for the original SIO device. Signed-off-by: Jarkko Huijts <jarkko.huijts@gmail.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>