From 301fe8eeee02c570c5bd30537aff9456f7f7955c Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Mon, 1 Feb 2010 12:34:31 -0800 Subject: [PATCH] omap: Disable serial port autoidle by default Currently the omap serial clocks are autoidled after 5 seconds. However, this causes lost characters on the serial ports. As this is considered non-standard behaviour for Linux, disable the timeout. Note that this will also cause blocking of any deeper omap sleep states. To enable the autoidling of the serial ports, do something like this for each serial port: # echo 5 > /sys/devices/platform/serial8250.0/sleep_timeout # echo 5 > /sys/devices/platform/serial8250.1/sleep_timeout ... Signed-off-by: Kevin Hilman Signed-off-by: Tony Lindgren --- arch/arm/mach-omap2/serial.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c index 8c964bec815..e10a02df6e1 100644 --- a/arch/arm/mach-omap2/serial.c +++ b/arch/arm/mach-omap2/serial.c @@ -36,7 +36,13 @@ #define UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV 0x52 #define UART_OMAP_WER 0x17 /* Wake-up enable register */ -#define DEFAULT_TIMEOUT (5 * HZ) +/* + * NOTE: By default the serial timeout is disabled as it causes lost characters + * over the serial ports. This means that the UART clocks will stay on until + * disabled via sysfs. This also causes that any deeper omap sleep states are + * blocked. + */ +#define DEFAULT_TIMEOUT 0 struct omap_uart_state { int num; @@ -422,7 +428,8 @@ static void omap_uart_idle_init(struct omap_uart_state *uart) uart->timeout = DEFAULT_TIMEOUT; setup_timer(&uart->timer, omap_uart_idle_timer, (unsigned long) uart); - mod_timer(&uart->timer, jiffies + uart->timeout); + if (uart->timeout) + mod_timer(&uart->timer, jiffies + uart->timeout); omap_uart_smart_idle_enable(uart, 0); if (cpu_is_omap34xx()) { -- 2.20.1