From: Qipan Li <Qipan.Li@xxxxxxx> A corner case exists in the current driver. if an app opens the console device, and before writing to console device, and there are huge kernel ogs to print out, system will hang on sirfsoc_uart_console_putchar: while (rd_regl(port, ureg->sirfsoc_tx_fifo_status) & ufifo_st->ff_full(port->line)) cpu_relax(); as in sirfsoc_uart_startup(), the driver assigns tx_fifo_op to 0 will stop TX FIFO, this loop will be endless. Signed-off-by: Qipan Li <Qipan.Li@xxxxxxx> Signed-off-by: Barry Song <Baohua.Song@xxxxxxx> --- drivers/tty/serial/sirfsoc_uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c index 8d75962..6b1c92c 100644 --- a/drivers/tty/serial/sirfsoc_uart.c +++ b/drivers/tty/serial/sirfsoc_uart.c @@ -272,6 +272,7 @@ static void sirfsoc_uart_start_tx(struct uart_port *port) if (sirfport->uart_reg->uart_type == SIRF_USP_UART) wr_regl(port, ureg->sirfsoc_tx_rx_en, rd_regl(port, ureg->sirfsoc_tx_rx_en) | SIRFUART_TX_EN); + wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_STOP); sirfsoc_uart_pio_tx_chars(sirfport, port->fifosize); wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_START); if (!sirfport->is_atlas7) @@ -1117,7 +1118,6 @@ static int sirfsoc_uart_startup(struct uart_port *port) SIRFSOC_USP_ENDIAN_CTRL_LSBF | SIRFSOC_USP_EN); wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_RESET); - wr_regl(port, ureg->sirfsoc_tx_fifo_op, 0); wr_regl(port, ureg->sirfsoc_rx_fifo_op, SIRFUART_FIFO_RESET); wr_regl(port, ureg->sirfsoc_rx_fifo_op, 0); wr_regl(port, ureg->sirfsoc_tx_fifo_ctrl, SIRFUART_FIFO_THD(port)); -- 2.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
