Merge tag 'tty-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull TTY/serial patches from Greg KH:
 "tty and serial merge for 3.4-rc1

  Here's the big serial and tty merge for the 3.4-rc1 tree.

  There's loads of fixes and reworks in here from Jiri for the tty
  layer, and a number of patches from Alan to help try to wrestle the vt
  layer into a sane model.

  Other than that, lots of driver updates and fixes, and other minor
  stuff, all detailed in the shortlog."

* tag 'tty-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (132 commits)
  serial: pxa: add clk_prepare/clk_unprepare calls
  TTY: Wrong unicode value copied in con_set_unimap()
  serial: PL011: clear pending interrupts
  serial: bfin-uart: Don't access tty circular buffer in TX DMA interrupt after it is reset.
  vt: NULL dereference in vt_do_kdsk_ioctl()
  tty: serial: vt8500: fix annotations for probe/remove
  serial: remove back and forth conversions in serial_out_sync
  serial: use serial_port_in/out vs serial_in/out in 8250
  serial: introduce generic port in/out helpers
  serial: reduce number of indirections in 8250 code
  serial: delete useless void casts in 8250.c
  serial: make 8250's serial_in shareable to other drivers.
  serial: delete last unused traces of pausing I/O in 8250
  pch_uart: Add module parameter descriptions
  pch_uart: Use existing default_baud in setup_console
  pch_uart: Add user_uartclk parameter
  pch_uart: Add Fish River Island II uart clock quirks
  pch_uart: Use uartclk instead of base_baud
  mpc5200b/uart: select more tolerant uart prescaler on low baudrates
  tty: moxa: fix bit test in moxa_start()
  ...

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/tty/serial/bfin_uart.c b/drivers/tty/serial/bfin_uart.c
index 26953bfa692..5832fdef11e 100644
--- a/drivers/tty/serial/bfin_uart.c
+++ b/drivers/tty/serial/bfin_uart.c
@@ -535,11 +535,13 @@ static irqreturn_t bfin_serial_dma_tx_int(int irq, void *dev_id)
 		 *		when start a new tx.
 		 */
 		UART_CLEAR_IER(uart, ETBEI);
-		xmit->tail = (xmit->tail + uart->tx_count) & (UART_XMIT_SIZE - 1);
 		uart->port.icount.tx += uart->tx_count;
+		if (!uart_circ_empty(xmit)) {
+			xmit->tail = (xmit->tail + uart->tx_count) & (UART_XMIT_SIZE - 1);
 
-		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
-			uart_write_wakeup(&uart->port);
+			if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+				uart_write_wakeup(&uart->port);
+		}
 
 		bfin_serial_dma_tx_chars(uart);
 	}