From: Aristeu Rozanski Date: Thu, 24 Jul 2008 04:29:45 +0000 (-0700) Subject: 8250: fix break handling for Intel 82571 X-Git-Tag: v2.6.27-rc1~666 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7500b1f602aad75901774a67a687ee985d85893f;p=linux-2.6 8250: fix break handling for Intel 82571 Intel 82571 has a "Serial Over LAN" feature that doesn't properly implements the receiving of break characters. When a break is received, it doesn't set UART_LSR_DR and unless another character is received, the break won't be received by the application. Signed-off-by: Aristeu Rozanski Acked-by: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 27f34a9f9c..a97f1ae11f 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1293,7 +1293,18 @@ receive_chars(struct uart_8250_port *up, unsigned int *status) char flag; do { - ch = serial_inp(up, UART_RX); + if (likely(lsr & UART_LSR_DR)) + ch = serial_inp(up, UART_RX); + else + /* + * Intel 82571 has a Serial Over Lan device that will + * set UART_LSR_BI without setting UART_LSR_DR when + * it receives a break. To avoid reading from the + * receive buffer without UART_LSR_DR bit set, we + * just force the read character to be 0 + */ + ch = 0; + flag = TTY_NORMAL; up->port.icount.rx++; @@ -1342,7 +1353,7 @@ receive_chars(struct uart_8250_port *up, unsigned int *status) ignore_char: lsr = serial_inp(up, UART_LSR); - } while ((lsr & UART_LSR_DR) && (max_count-- > 0)); + } while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (max_count-- > 0)); spin_unlock(&up->port.lock); tty_flip_buffer_push(tty); spin_lock(&up->port.lock); @@ -1425,7 +1436,7 @@ serial8250_handle_port(struct uart_8250_port *up) DEBUG_INTR("status = %x...", status); - if (status & UART_LSR_DR) + if (status & (UART_LSR_DR | UART_LSR_BI)) receive_chars(up, &status); check_modem_status(up); if (status & UART_LSR_THRE)