diff options
| author | Aristeu Rozanski <arozansk@redhat.com> | 2008-07-23 21:29:45 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-24 10:47:29 -0700 |
| commit | 7500b1f602aad75901774a67a687ee985d85893f (patch) | |
| tree | 52afbdf19a5186e307fa9da68a1070431ad46b3a /drivers/serial | |
| parent | 920519c1c31ca46ef6caab1a4be102ed0dfb5fbc (diff) | |
| download | lwn-7500b1f602aad75901774a67a687ee985d85893f.tar.gz lwn-7500b1f602aad75901774a67a687ee985d85893f.zip | |
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 <arozansk@redhat.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/serial')
| -rw-r--r-- | drivers/serial/8250.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 27f34a9f9cb7..a97f1ae11f78 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) |