[Piglit] [PATCH] glx: Rerun failing tests in auto mode if there is a pending expose event

[Brian Paul]

On 09/26/2017 10:32 AM, Thomas Hellstrom wrote:
> Tests that check frontbuffer contents after drawing may fail because
> the X server touch the front contents between drawing and checking. In those
> cases, there's typically a pending expose event. So check for that
> situation and optionally rerun the test.

Maybe a little word-smithing:

"
Tests that check the frontbuffer contents after drawing may fail because
the X server may touch the front contents between drawing and reading.
In those cases, there's typically a pending expose event. So check for 
that situation and rerun the test.
"

>
> Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
> ---
>   tests/util/piglit-glx-util.c | 14 ++++++++++++++
>   1 file changed, 14 insertions(+)
>
> diff --git a/tests/util/piglit-glx-util.c b/tests/util/piglit-glx-util.c
> index 95e33ae..85f7eef 100644
> --- a/tests/util/piglit-glx-util.c
> +++ b/tests/util/piglit-glx-util.c
> @@ -212,6 +212,20 @@ piglit_glx_event_loop(Display *dpy, enum piglit_result (*draw)(Display *dpy))
>   			enum piglit_result result = draw(dpy);
>
>   			if (piglit_automatic) {
> +				/*
> +				 * Rerun if we have failed and have a
> +				 * pending expose event, which might be an
> +				 * indication of invalid front buffer
> +				 * contents.
> +				 */
> +				if (result == PIGLIT_FAIL &&
> +				    XCheckTypedEvent(dpy, Expose, &event)) {
> +					fprintf(stderr,
> +						"Pending expose event- "
> +						"rerunning.\n");
> +					XPutBackEvent(dpy, &event);
> +					continue;
> +				}
>   				XCloseDisplay(dpy);
>   				piglit_report_result(result);
>   				break;
>

I think the problem you describe could also happen when we're not 
running in automatic mode.  Therefore, I think the new code could be put 
before the if (piglit_automatic) block.  What do you think?

-Brian