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.southw...@yahoo.com>
> ---
> 
> 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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