[igt-dev] [PATCH i-g-t] tests/kms_big_fb: Wait for vblank before collecting CRC

[Srinivas, Vidya]

Hello Juha-Pekka

We are seeing the CRC failures on Jasperlake systems. Sometimes the test passes and sometimes it fails throwing CRC error.

Regards
Vidya

-----Original Message-----
From: Juha-Pekka Heikkila <juhapekka.heikkila at gmail.com> 
Sent: Friday, May 21, 2021 5:00 PM
To: Srinivas, Vidya <vidya.srinivas at intel.com>; intel-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org; igt-dev at lists.freedesktop.org
Cc: Lin, Charlton <charlton.lin at intel.com>
Subject: Re: [igt-dev] [PATCH i-g-t] tests/kms_big_fb: Wait for vblank before collecting CRC

Hi Vidya,

on which machines this would help? I see there's many vblanks already being waited. There's igt_display_commit2 which probably will block and even if it didn't there's igt_pipe_crc_collect_crc(..) where crc calculation is started after flip and then get one crc before disabling crc counting again.

/Juha-Pekka

On 21.5.2021 7.08, Vidya Srinivas wrote:
> Without wait for vblank, CRC mismatch is seen between big and small 
> CRC on few systems
> 
> Change-Id: I3bec931aa901130997e693ac1cacf389e2a8100f
> Signed-off-by: Vidya Srinivas <vidya.srinivas at intel.com>
> ---
>   tests/kms_big_fb.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/kms_big_fb.c b/tests/kms_big_fb.c index 
> b2027b6b9d1b..7d78ff829d41 100644
> --- a/tests/kms_big_fb.c
> +++ b/tests/kms_big_fb.c
> @@ -254,6 +254,7 @@ static void unset_lut(data_t *data)
>   static bool test_plane(data_t *data)
>   {
>   	igt_plane_t *plane = data->plane;
> +	igt_display_t *display = &data->display;
>   	struct igt_fb *small_fb = &data->small_fb;
>   	struct igt_fb *big_fb = &data->big_fb;
>   	int w = data->big_fb_width - small_fb->width; @@ -337,16 +338,17 @@ 
> static bool test_plane(data_t *data)
>   		igt_display_commit2(&data->display, data->display.is_atomic ?
>   				    COMMIT_ATOMIC : COMMIT_UNIVERSAL);
>   
> -
> +		igt_wait_for_vblank(data->drm_fd, 
> +display->pipes[data->pipe].crtc_offset);
>   		igt_pipe_crc_collect_crc(data->pipe_crc, &small_crc);
>   
>   		igt_plane_set_fb(plane, big_fb);
>   		igt_fb_set_position(big_fb, plane, x, y);
>   		igt_fb_set_size(big_fb, plane, small_fb->width, small_fb->height);
> +
>   		igt_plane_set_size(plane, data->width, data->height);
>   		igt_display_commit2(&data->display, data->display.is_atomic ?
>   				    COMMIT_ATOMIC : COMMIT_UNIVERSAL);
> -
> +		igt_wait_for_vblank(data->drm_fd, 
> +display->pipes[data->pipe].crtc_offset);
>   		igt_pipe_crc_collect_crc(data->pipe_crc, &big_crc);
>   
>   		igt_plane_set_fb(plane, NULL);
>