| Message ID | 1397198188-8602-1-git-send-email-harinik@xilinx.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | eee668a92bc775030178c8a7f0d0abe9cce441d7 |
| Headers | show |
On Fri, Apr 11, 2014 at 12:06:28PM +0530, Harini Katakam wrote: > The existing timeout value in wait_for_completion_timeout is > calculated from the transfer length and speed with tolerance of 10msec. > This is too low because this is used for error conditions such as > hardware hang etc. Applied, thanks.
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 4eb9bf0..f01cbb4 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -775,7 +775,7 @@ static int spi_transfer_one_message(struct spi_master *master, if (ret > 0) { ret = 0; ms = xfer->len * 8 * 1000 / xfer->speed_hz; - ms += 10; /* some tolerance */ + ms += ms + 100; /* some tolerance */ ms = wait_for_completion_timeout(&master->xfer_completion, msecs_to_jiffies(ms));
The existing timeout value in wait_for_completion_timeout is calculated from the transfer length and speed with tolerance of 10msec. This is too low because this is used for error conditions such as hardware hang etc. The xfer->speed_hz considered may not be the actual speed set because the best clock divisor is chosen from a limited set such that the actual speed <= requested speed. This will lead to timeout being less than actual transfer time. Considering acceptable latencies, this timeout can be set to a value double the expected transfer plus 100 msecs. This patch adds the same in the core. Signed-off-by: Harini Katakam <harinik@xilinx.com> --- v2 changes: Decrease timeout - make it double of expected time + 100ms --- drivers/spi/spi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)