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Message-ID: <20090115133050.21366.18907.stgit@localhost.localdomain>
Date: Thu, 15 Jan 2009 13:30:56 +0000
From: Alan Cox <alan@...rguk.ukuu.org.uk>
To: torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: [PATCH 4/8] When a break signal is detected,
the next character should be ignored.
From: Mischa Jonker <mischa.jonker@....com>
This was not implemented correctly for the pnx8xxx_uart driver.
[From further discussion:
Correct, you can look to it as two separate bugs:
a) the next character is not ignored while it should;
b) the status bits 31-8 are copied to the 'ch' variable while they shouldn't.
Both bugs prevent correct break signal handling (and therefore correct
behaviour of the magic SysRq key). Bug b didn't cause too much trouble
earlier because in most situations the status bits are all zero; for
this case they unfortunately aren't.
]
Signed-off-by: Mischa Jonker <mischa.jonker@....com>
Signed-off-by: Alan Cox <alan@...hat.com>
---
drivers/serial/pnx8xxx_uart.c | 23 ++++++++++++-----------
1 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/serial/pnx8xxx_uart.c b/drivers/serial/pnx8xxx_uart.c
index 22e30d2..1bb8f1b 100644
--- a/drivers/serial/pnx8xxx_uart.c
+++ b/drivers/serial/pnx8xxx_uart.c
@@ -187,7 +187,7 @@ static void pnx8xxx_rx_chars(struct pnx8xxx_port *sport)
status = FIFO_TO_SM(serial_in(sport, PNX8XXX_FIFO)) |
ISTAT_TO_SM(serial_in(sport, PNX8XXX_ISTAT));
while (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFIFO)) {
- ch = serial_in(sport, PNX8XXX_FIFO);
+ ch = serial_in(sport, PNX8XXX_FIFO) & 0xff;
sport->port.icount.rx++;
@@ -198,9 +198,16 @@ static void pnx8xxx_rx_chars(struct pnx8xxx_port *sport)
* out of the main execution path
*/
if (status & (FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE |
- PNX8XXX_UART_FIFO_RXPAR) |
+ PNX8XXX_UART_FIFO_RXPAR |
+ PNX8XXX_UART_FIFO_RXBRK) |
ISTAT_TO_SM(PNX8XXX_UART_INT_RXOVRN))) {
- if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR))
+ if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXBRK)) {
+ status &= ~(FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE) |
+ FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR));
+ sport->port.icount.brk++;
+ if (uart_handle_break(&sport->port))
+ goto ignore_char;
+ } else if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXPAR))
sport->port.icount.parity++;
else if (status & FIFO_TO_SM(PNX8XXX_UART_FIFO_RXFE))
sport->port.icount.frame++;
@@ -284,14 +291,8 @@ static irqreturn_t pnx8xxx_int(int irq, void *dev_id)
/* Get the interrupts */
status = serial_in(sport, PNX8XXX_ISTAT) & serial_in(sport, PNX8XXX_IEN);
- /* Break signal received */
- if (status & PNX8XXX_UART_INT_BREAK) {
- sport->port.icount.brk++;
- uart_handle_break(&sport->port);
- }
-
- /* Byte received */
- if (status & PNX8XXX_UART_INT_RX)
+ /* Byte or break signal received */
+ if (status & (PNX8XXX_UART_INT_RX | PNX8XXX_UART_INT_BREAK))
pnx8xxx_rx_chars(sport);
/* TX holding register empty - transmit a byte */
--
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