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The implementation of flushing the RX FIFO breaks in a number of cases, it is impossible to ensure an complete flush of the RX FIFO due to the hardware not allowing the use of the FIFOs when the receiver is disabled (Reading from the FIFO register does not remove it from the FIFO when the RX_EN=0 or RX_DIS=1). Additionally during an initial set_termios call where RX_DIS=1 causes a hang waiting forever for the RX FIFO to empty. On top of this the FIFO will be cleared by the use of the RXRST bits on the Control Register, making the RX flush pointless (as it does not preserve the data read anyway). Due to the TXRST the TX FIFO and transmitter can be interrupted during frame trasmission, causing corruption and additionally data lost in the FIFO. Most other serial drivers do not flush or clear the FIFOs during a termios configuration change and as such do not have issues with corruption. For this UART controller is it required that the TXRST/RXRST bit be flagged during the change, this means that the data in the FIFO will be dropped when changing configuration. In order to prevent data loss and corruption of the transmitted data, wait until the TX FIFO is empty before changing the configuration. The performance of this may cause the set_termios call to take a longer amount of time especially on lower baud rates, however it is comparable to the same performance hit that a console_write call costs. Signed-off-by: Nathan Rossi <nathan.rossi@xilinx.com> Acked-by: Anirudha Sarangi <anirudh@xilinx.com> Acked-by: Harini Katakam <harinik@xilinx.com> Signed-off-by: Michal Simek <michal.simek@xilinx.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| .. | ||
| hvc | ||
| ipwireless | ||
| serial | ||
| vt | ||
| amiserial.c | ||
| bfin_jtag_comm.c | ||
| cyclades.c | ||
| ehv_bytechan.c | ||
| goldfish.c | ||
| isicom.c | ||
| Kconfig | ||
| Makefile | ||
| metag_da.c | ||
| moxa.c | ||
| moxa.h | ||
| mxser.c | ||
| mxser.h | ||
| n_gsm.c | ||
| n_hdlc.c | ||
| n_r3964.c | ||
| n_tracerouter.c | ||
| n_tracesink.c | ||
| n_tracesink.h | ||
| n_tty.c | ||
| nozomi.c | ||
| pty.c | ||
| rocket_int.h | ||
| rocket.c | ||
| rocket.h | ||
| synclink_gt.c | ||
| synclink.c | ||
| synclinkmp.c | ||
| sysrq.c | ||
| tty_audit.c | ||
| tty_buffer.c | ||
| tty_io.c | ||
| tty_ioctl.c | ||
| tty_ldisc.c | ||
| tty_ldsem.c | ||
| tty_mutex.c | ||
| tty_port.c | ||