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authorJason Wessel <jason.wessel@windriver.com>2010-05-20 22:04:22 -0400
committerJason Wessel <jason.wessel@windriver.com>2010-05-20 22:04:22 -0400
commitf5316b4aea024da9266d740322a5481657f6ce59 (patch)
tree5888fd0afa54fc3bab2711e583147c4b563836bc /drivers/serial/8250.c
parentdcc7871128e99458ca86186b7bc8bf27ff0c47b5 (diff)
kgdb,8250,pl011: Return immediately from console poll
The design of the kdb shell requires that every device that can provide input to kdb have a polling routine that exits immediately if there is no character available. This is required in order to get the page scrolling mechanism working. Changing the kernel debugger I/O API to require all polling character routines to exit immediately if there is no data allows the kernel debugger to process multiple input channels. NO_POLL_CHAR will be the return code to the polling routine when ever there is no character available. CC: linux-serial@vger.kernel.org Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Diffstat (limited to 'drivers/serial/8250.c')
-rw-r--r--drivers/serial/8250.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 2b1ea3d4c4f4..891e1dd65f24 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1891,8 +1891,8 @@ static int serial8250_get_poll_char(struct uart_port *port)
1891 struct uart_8250_port *up = (struct uart_8250_port *)port; 1891 struct uart_8250_port *up = (struct uart_8250_port *)port;
1892 unsigned char lsr = serial_inp(up, UART_LSR); 1892 unsigned char lsr = serial_inp(up, UART_LSR);
1893 1893
1894 while (!(lsr & UART_LSR_DR)) 1894 if (!(lsr & UART_LSR_DR))
1895 lsr = serial_inp(up, UART_LSR); 1895 return NO_POLL_CHAR;
1896 1896
1897 return serial_inp(up, UART_RX); 1897 return serial_inp(up, UART_RX);
1898} 1898}