Re: [PATCH i-g-t v2 1/1] tests/kms_color: Add 10-bit color depth support to gamma test for MediaTek

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 13 Apr 2026, Jay Liu <jay.liu@mediatek.com> wrote:
> 1. Add 10-bit color depth flow to gamma test for MediaTek devices, which only
> support bit-true results with 10-bit data. The test now selects 8-bit or
> 10-bit color depth and framebuffer format based on device type.
>
> 2. To satisfy the legacy gamma test requirements, the MTK Gamma LUT limit
> should be set to 4092, in the current 16-bit LUT design, setting the entry
>  to 0xffd0 ensures the driver maps it correctly to 4092.
>
> Signed-off-by: Jay Liu <jay.liu@mediatek.com>
> ---
>  tests/kms_color.c | 35 +++++++++++++++++++++++++++--------
>  1 file changed, 27 insertions(+), 8 deletions(-)
>
> diff --git a/tests/kms_color.c b/tests/kms_color.c
> index 565edb2dc..033207368 100644
> --- a/tests/kms_color.c
> +++ b/tests/kms_color.c
> @@ -288,7 +288,7 @@ static bool test_pipe_legacy_gamma(data_t *data,
>  	fb_id = igt_create_fb(data->drm_fd,
>  			      mode->hdisplay,
>  			      mode->vdisplay,
> -			      DRM_FORMAT_XRGB8888,
> +			      data->drm_format,
>  			      DRM_FORMAT_MOD_LINEAR,
>  			      &fb);
>  	igt_assert(fb_id);
> @@ -296,7 +296,7 @@ static bool test_pipe_legacy_gamma(data_t *data,
>  	fb_modeset_id = igt_create_fb(data->drm_fd,
>  				      mode->hdisplay,
>  				      mode->vdisplay,
> -				      DRM_FORMAT_XRGB8888,
> +				      data->drm_format,
>  				      DRM_FORMAT_MOD_LINEAR,
>  				      &fb_modeset);
>  	igt_assert(fb_modeset_id);
> @@ -322,9 +322,20 @@ static bool test_pipe_legacy_gamma(data_t *data,
>  	igt_plane_set_fb(primary, &fb);
>  
>  	red_lut[0] = green_lut[0] = blue_lut[0] = 0;
> -	for (i = 1; i < legacy_lut_size; i++)
> -		red_lut[i] = green_lut[i] = blue_lut[i] = 0xffff;
> -	igt_assert_eq(drmModeCrtcSetGamma(data->drm_fd, primary->crtc->crtc_id,
> +	for (i = 1; i < legacy_lut_size; i++) {
> +		/*
> +		 * The Medaitek Gamma LUT maps 10bit input data to 12bit output.
> +		 * In this test case, the maximum input value is 1023.
> +		 * When the Gamma function is disabled, the data defaults to a 4092 output.
> +		 * To achieve bit true results, the Gamma LUT maximum must be set to 4092.
> +		 * Note that 0xFFFD0 represents 16-bit,which maps to 4092 in 12-bit depth.
> +		 */
> +		if (is_mtk_device(data->drm_fd))
> +			red_lut[i] = green_lut[i] = blue_lut[i] = 0xffd0;
> +		else
> +			red_lut[i] = green_lut[i] = blue_lut[i] = 0xffff;
> +	}
> +	igt_assert_eq(drmModeCrtcSetGamma(data->drm_fd, primary->pipe->crtc_id,
>  					  legacy_lut_size, red_lut, green_lut, blue_lut), 0);

This does not compile.

>  	igt_display_commit(&data->display);
>  	igt_wait_for_vblank(primary->crtc);
> @@ -752,14 +763,22 @@ static void
>  run_gamma_degamma_tests_for_crtc(data_t *data, igt_crtc_t *crtc,
>  				 bool (*test_t)(data_t*, igt_plane_t*))
>  {
> +	bool is_mtk = false;
> +
>  	test_setup(data, crtc);
>  
> +	/* MediaTek requires 10-bit pipeline for accurate (bit true) color processing */
> +	if (is_mtk_device(data->drm_fd))
> +		is_mtk = true;
> +
>  	/*
> -	 * We assume an 8bits depth per color for degamma/gamma LUTs
> +	 * We assume an 8bits or 10bits depth per color for degamma/gamma LUTs
>  	 * for CRC checks with framebuffer references.
>  	 */
> -	data->color_depth = 8;
> -	data->drm_format = DRM_FORMAT_XRGB8888;
> +
> +	/* MediaTek requires 10-bit pipeline for accurate (bit true) color processing */
> +	data->color_depth = is_mtk ? 10 : 8;
> +	data->drm_format = is_mtk ? DRM_FORMAT_XRGB2101010 : DRM_FORMAT_XRGB8888;
>  	data->mode = igt_output_get_mode(data->output);
>  
>  	igt_require(crtc_output_combo_valid(data, crtc));

-- 
Jani Nikula, Intel