From 59733ef7e510f6fd51a3dfc6f22ec1d3630a47b9 Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy@c-s.fr>
Date: Mon, 24 Sep 2012 08:19:03 +0200
Subject: [PATCH] Powerpc 8xx CPM_UART too many interrupts
Setting the fifo to only 1 byte generates one interrupt every 1ms at 9600 bauds.
This is too much. This patch reduces the threshold to speeds below 2400 bauds
like in the 8250 UART driver.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/cpm_uart/cpm_uart_core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/cpm_uart/cpm_uart_core.c b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
index 46af6e47f061..46edc649b0b7 100644
--- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
@@ -71,7 +71,7 @@ static void cpm_uart_initbd(struct uart_cpm_port *pinfo);
/**************************************************************/
-#define HW_BUF_SPD_THRESHOLD 9600
+#define HW_BUF_SPD_THRESHOLD 2400
/*
* Check, if transmit buffers are processed
@@ -505,7 +505,7 @@ static void cpm_uart_set_termios(struct uart_port *port,
pr_debug("CPM uart[%d]:set_termios\n", port->line);
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
- if (baud <= HW_BUF_SPD_THRESHOLD ||
+ if (baud < HW_BUF_SPD_THRESHOLD ||
(pinfo->port.state && pinfo->port.state->port.tty->low_latency))
pinfo->rx_fifosize = 1;
else
--
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