[PATCH weston] compositor: warn about insane repaint delay

[Derek Foreman]

Reviewed-By: Derek Foreman <derekf at osg.samsung.com>

On 19/03/15 05:33 AM, Pekka Paalanen wrote:
> From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> 
> Make the sanity check more explicit and log a warning if it happens.
> 
> Small negative values are ok because it just means the compositor is
> lagging behind, or more likely the user specified a too long repaint
> window.
> 
> Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> ---
>  src/compositor.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/src/compositor.c b/src/compositor.c
> index 3f6aa7d..be2309a 100644
> --- a/src/compositor.c
> +++ b/src/compositor.c
> @@ -2412,8 +2412,18 @@ weston_output_finish_frame(struct weston_output *output,
>  	msec = (refresh_nsec - timespec_to_nsec(&gone)) / 1000000; /* floor */
>  	msec -= compositor->repaint_msec;
>  
> -	/* Also sanity check. */
> -	if (msec < 1 || msec > 1000)
> +	if (msec < -1000 || msec > 1000) {
> +		static bool warned;
> +
> +		if (!warned)
> +			weston_log("Warning: computed repaint delay is "
> +				   "insane: %d msec\n", msec);
> +		warned = true;
> +
> +		msec = 0;
> +	}
> +
> +	if (msec < 1)
>  		output_repaint_timer_handler(output);
>  	else
>  		wl_event_source_timer_update(output->repaint_timer, msec);
>