On Tue, 2014-01-14 at 13:38 -0600, Chase Southwood wrote:
> This patch to ni_mio_common.c changes a while loop to a timeout for
> loop, which is preferred.
>
> Signed-off-by: Chase Southwood <chase.southwood@xxxxxxxxx>
> ---
>
> I know Mr. Abbott mentioned that he wouldn't expect clean-up patches to have to deal with this sort of thing, but I thought I'd at least give the timeout thing a try. Feel free to disregard this and take v1 of this patch instead if you would just like the simple clean-up. That being said, I used 10000 iterations at the suggestion of Mr. Abbott, and a short delay as well. Let me know if these values seem incorrect. Also, at some (but not all) locations in this file that currently use timeouts, contain a check for i == timeout, with a call to either printk or comedi_error if the operation actually times out. Would something like that be required here?
>
> Sorry for all of the questions, but I'm sort of new around here and I'd like to help out with more than just clean-ups and this seemed like a good opportunity to at least try!
>
> 2: Changed from simple clean-up to swapping a timeout in for a while loop.
>
> drivers/staging/comedi/drivers/ni_mio_common.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
> index 457b884..05cd5ed 100644
> --- a/drivers/staging/comedi/drivers/ni_mio_common.c
> +++ b/drivers/staging/comedi/drivers/ni_mio_common.c
> @@ -687,12 +687,19 @@ static void ni_clear_ai_fifo(struct comedi_device *dev)
> {
> const struct ni_board_struct *board = comedi_board(dev);
> struct ni_private *devpriv = dev->private;
> + static const int timeout = 10000;
> + int i;
>
> if (board->reg_type == ni_reg_6143) {
> /* Flush the 6143 data FIFO */
> ni_writel(0x10, AIFIFO_Control_6143); /* Flush fifo */
> ni_writel(0x00, AIFIFO_Control_6143); /* Flush fifo */
> - while (ni_readl(AIFIFO_Status_6143) & 0x10) ; /* Wait for complete */
> + /* Wait for complete */
> + for (i = 0; i < timeout; i++) {
> + if(!(ni_readl(AIFIFO_Status_6143) & 0x10))
> + break;
> + udelay(1);
> + }
some sort of error message would be nice too
if (i >= timeout)
comedi_error(dev, "FIFO flush timeout");
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