Re: [PATCH i-g-t v4 7/7] tests/intel/kms_pm_dc: Add dc3co-vpb-framegap subtest

["Naladala, Ramanaidu" <Ramanaidu.naladala@intel.com>]

Hi Jeevan,

On 5/11/2026 10:48 PM, Jeevan B wrote:
> Add a new subtest to validate DC3CO counter increments across
> frame gaps exceeding the threshold during a video-like workload
> with PSR2 enabled.
>
> Signed-off-by: Jeevan B <jeevan.b@intel.com>
> ---
>   tests/intel/kms_pm_dc.c | 69 +++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 69 insertions(+)
>
> diff --git a/tests/intel/kms_pm_dc.c b/tests/intel/kms_pm_dc.c
> index 6d2bd0ee1..b8d903fd5 100644
> --- a/tests/intel/kms_pm_dc.c
> +++ b/tests/intel/kms_pm_dc.c
> @@ -60,6 +60,10 @@
>    *              exit cycle, ensuring DC3CO is not broken by deeper power state
>    *              transitions.
>    *
> + * SUBTEST: dc3co-vpb-framegap
> + * Description: Validate DC3CO counter increments before and after a delay greater
> + *              than 6 frame gaps during video-like load with PSR2 active.
> + *
>    * SUBTEST: dc5-dpms
>    * Description: Validate display engine entry to DC5 state while all connectors's
>    *              DPMS property set to OFF
> @@ -433,6 +437,63 @@ static void test_dc3co_framedrop(data_t *data, enum psr_mode mode)
>   	cleanup_dc3co_fbs(data);
>   }
>   
> +static void check_dc3co_with_framegap_load(data_t *data)
> +{
> +	igt_plane_t *primary;
> +	uint32_t dc3co_cnt_before, dc3co_cnt_after_gap;
> +	int delay, long_gap_us;
> +	time_t secs = 3;
> +	time_t start_time;
> +
> +	primary = igt_output_get_plane_type(data->output, DRM_PLANE_TYPE_PRIMARY);
> +	igt_plane_set_fb(primary, NULL);
> +
> +	delay = 1.5 * ((1000 * 1000) / data->mode->vrefresh);
> +
> +	dc3co_cnt_before = igt_read_dc_counter(data->debugfs_fd,
> +			   IGT_INTEL_CHECK_DC3CO);
> +	start_time = time(NULL);
> +	while (time(NULL) - start_time < secs) {
> +		igt_plane_set_fb(primary, &data->fb_rgb);
> +		igt_display_commit(&data->display);
> +		usleep(delay);
> +
> +		igt_plane_set_fb(primary, &data->fb_rgr);
> +		igt_display_commit(&data->display);
> +		usleep(delay);
> +	}
Imho, instead of using loops and delay calculations use 
igt_wait_for_vblank_count() helper to delay required number of frames.
> +
> +	assert_dc_counter(data, IGT_INTEL_CHECK_DC3CO, dc3co_cnt_before);
> +
> +	long_gap_us = 7 * ((1000 * 1000) / data->mode->vrefresh);
> +	usleep(long_gap_us);
> +
> +	dc3co_cnt_after_gap = igt_read_dc_counter(data->debugfs_fd,
> +						  IGT_INTEL_CHECK_DC3CO);
> +	start_time = time(NULL);
> +	while (time(NULL) - start_time < secs) {
> +		igt_plane_set_fb(primary, &data->fb_rgb);
> +		igt_display_commit(&data->display);
> +		usleep(delay);
> +
> +		igt_plane_set_fb(primary, &data->fb_rgr);
> +		igt_display_commit(&data->display);
> +		usleep(delay);
> +	}
> +
> +	assert_dc_counter(data, IGT_INTEL_CHECK_DC3CO, dc3co_cnt_after_gap);
> +}
> +
> +static void test_dc3co_vpb_framegap(data_t *data)
> +{
> +	igt_require_dc_counter(data->debugfs_fd, IGT_INTEL_CHECK_DC3CO);
> +	setup_output(data);
> +	setup_dc3co(data, PSR_MODE_2);
> +	setup_videoplayback(data);
> +	check_dc3co_with_framegap_load(data);
> +	cleanup_dc3co_fbs(data);
> +}
> +
>   static void test_dc5_retention_flops(data_t *data, int dc_flag)
>   {
>   	uint32_t dc_counter_before_psr;
> @@ -864,6 +925,14 @@ int igt_main()
>   		}
>   	}
>   
> +	igt_describe("Validate DC3CO counter increments before and after a delay "
> +		     "greater than 6 frame gaps during video-like load with PSR2 active");
> +	igt_subtest("dc3co-vpb-framegap") {
> +		igt_require(psr_sink_support(data.drm_fd, data.debugfs_fd,
> +					     PSR_MODE_2, NULL));
> +		test_dc3co_vpb_framegap(&data);
> +	}
> +
>   	igt_describe("This test validates display engine entry to DC5 state "
>   		     "while PSR is active");
>   	igt_subtest("dc5-psr") {