From: Gabriel Matni firstname.lastname@example.org
Fixes missing characters on kernel console at low baud rates (i.e.9600). The driver should poll TX_RDY or TX_FIFO_EMP instead of TX_EMP to ensure that the transmitter holding register (THR) is ready to receive a new byte.
TX_EMP tells us when it is possible to send a break sequence via SND_BRK_SEQ. While this also indicates that both the THR and the TSR are empty, it does not guarantee that a new byte can be written just yet.
Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port") Reviewed-by: Miquel Raynal email@example.com Acked-by: Gregory CLEMENT firstname.lastname@example.org Signed-off-by: Gabriel Matni email@example.com --- Changes since v3: - mail the patch in a clean email - fix the subject line accordingly (no Re:)
Changes since v2: - use one line for the "Fixes" entry - removed trailing space between Signed-off-by entry and --- - start using versioning, previous fixes in v1
Changes since v1: - patch was corrupt, could not be applied - fixed line indent --- drivers/tty/serial/mvebu-uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index a100e98259d7..f0df0640208e 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -618,7 +618,7 @@ static void wait_for_xmitr(struct uart_port *port) u32 val;
readl_poll_timeout_atomic(port->membase + UART_STAT, val, - (val & STAT_TX_EMP), 1, 10000); + (val & STAT_TX_RDY(port)), 1, 10000); }
static void mvebu_uart_console_putchar(struct uart_port *port, int ch)