Re: [PATCH v2] staging: greybus: loopback: Use fsleep() for delay

[Alex Elder]

On 10/22/26 3:24 PM, pavankumaryalagada@xxxxxxxxx wrote:
> From: Yalagada Pavan Kumar <pavankumaryalagada@xxxxxxxxx>
>
> In the loopback function, usleep_range() is used for short delays
> and msleep() for longer delays. This requires choosing the delay
> function based on the requested time and converting microseconds
> to milliseconds when using msleep().
>
> Replace both functions with fsleep(), which chooses a delay
> delay method based on the requested time. For short delays,

s/delay delay/delay/

I think "checkpatch.pl" would have caught this.

Maybe Greg can fix this up.


> fsleep() allows up to 25% extra time instead of the fixed 100
> microseconds. For longer delays, the old code rounds the
> requested time down to whole milliseconds, while fsleep() rounds
> it up when using msleep().
>
> These changes may affect time between loopback operations and
> the reported performance.
>
> Suggested-by: Alex Elder <elder@xxxxxxxxxxxx>
> Signed-off-by: Yalagada Pavan Kumar <pavankumaryalagada@xxxxxxxxx>

Looks good to me.  Nice job.

Reviewed-by: Alex Elder <elder@xxxxxxxxxxxx>

> ---
> v2:
> - Add more details about how fsleep() affects delays.
> - Update the subject to include the loopback module.
>
> v1: https://lore.kernel.org/outreachy/c482704b-903e-413d-ba7b-5bf31c0a6104@xxxxxxxxxxxx/T/#t
> ---
>   drivers/staging/greybus/loopback.c | 8 ++------
>   1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c
> index efc69c10cffe..2fe845eaef29 100644
> --- a/drivers/staging/greybus/loopback.c
> +++ b/drivers/staging/greybus/loopback.c
> @@ -898,12 +898,8 @@ static int gb_loopback_fn(void *data)
>   		gb->send_count++;
>   		mutex_unlock(&gb->mutex);
>   
> -		if (us_wait) {
> -			if (us_wait < 20000)
> -				usleep_range(us_wait, us_wait + 100);
> -			else
> -				msleep(us_wait / 1000);
> -		}
> +		if (us_wait)
> +			fsleep(us_wait);
>   	}
>   
>   	gb_pm_runtime_put_autosuspend(bundle);