From: Anil Veliyankara Madam <aveliyan@xxxxxxxxx> Since msleep() may sleep longer than intended time for values less than 20ms, this patch allows the use of usleep_range for waits less that 20ms. usleep_range is a finer precision implementation of msleep and is designed to be a drop-in replacement for udelay where a precise sleep/busy-wait is unnecessary. More details can be found at http://lkml.org/lkml/2007/8/3/250 and in Documentation/timers/timers-howto.txt. This change has been done to improve the performace in PIO6 mode which is used by viking flash. Cc: xe-kernel@xxxxxxxxxxxxxxxxxx Signed-off-by: Anil Veliyankara Madam <aveliyan@xxxxxxxxx> Signed-off-by: Shikha Jain <shikjain@xxxxxxxxx> --- drivers/ata/libata-core.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index b79cb10..3abf0ea 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -50,6 +50,7 @@ #include <linux/blkdev.h> #include <linux/delay.h> #include <linux/timer.h> +#include <linux/time.h> #include <linux/interrupt.h> #include <linux/completion.h> #include <linux/suspend.h> @@ -6697,7 +6698,12 @@ void ata_msleep(struct ata_port *ap, unsigned int msecs) if (owns_eh) ata_eh_release(ap); - msleep(msecs); + if (msecs < 20) { + unsigned long usecs = msecs * USEC_PER_MSEC; + usleep_range(usecs, usecs + 50); + } else { + msleep(msecs); + } if (owns_eh) ata_eh_acquire(ap); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
