Re: [PATCH i-g-t] tests/intel/kms_cdclk: Skip CDCLK bump validation when dotclocks match

[Karthik B S <karthik.b.s@intel.com>]

On 4/10/2026 6:11 PM, Swati Sharma wrote:
> When the highest and lowest resolution modes share the same dotclock,
> no CDCLK bump is expected.
>
> Skip CDCLK bump validation when the highres and lowres modes have the
> same dotclock, replacing the previous resolution-based is_equal() check
> with a dotclock comparison via has_same_dotclock().
>
> Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
Reviewed-by: Karthik B S <karthik.b.s@intel.com>
> ---
>   tests/intel/kms_cdclk.c | 12 +++++-------
>   1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/tests/intel/kms_cdclk.c b/tests/intel/kms_cdclk.c
> index 662bdbe43..48bd7276f 100644
> --- a/tests/intel/kms_cdclk.c
> +++ b/tests/intel/kms_cdclk.c
> @@ -84,11 +84,9 @@ static bool is_4k(drmModeModeInfo mode)
>   	        mode.vrefresh >= VREFRESH);
>   }
>   
> -static bool is_equal(drmModeModeInfo mode_hi, drmModeModeInfo mode_lo)
> +static bool has_same_dotclock(drmModeModeInfo mode_hi, drmModeModeInfo mode_lo)
>   {
> -	return (mode_hi.hdisplay == mode_lo.hdisplay &&
> -		mode_hi.vdisplay == mode_lo.vdisplay &&
> -		mode_hi.vrefresh == mode_lo.vrefresh);
> +	return mode_hi.clock == mode_lo.clock;
>   }
>   
>   static drmModeModeInfo *get_lowres_mode(igt_output_t *output)
> @@ -204,7 +202,7 @@ static void test_mode_transition(data_t *data, igt_crtc_t *crtc,
>   	igt_require_f(is_4k(mode_hi), "Mode >= 4K not found on output %s\n",
>   	              igt_output_name(output));
>   
> -	igt_skip_on_f(is_equal(mode_hi, mode_lo), "Highest and lowest mode resolutions are same; no transition\n");
> +	igt_skip_on_f(has_same_dotclock(mode_hi, mode_lo), "Highest and lowest modes have same dotclock; no CDCLK bump expected\n");
>   
>   	primary = igt_output_get_plane_type(output, DRM_PLANE_TYPE_PRIMARY);
>   
> @@ -278,8 +276,8 @@ static void test_mode_transition_on_all_outputs(data_t *data)
>   
>   		mode_lowres[count] = *get_lowres_mode(output);
>   
> -		if (is_equal(mode_highres[count], mode_lowres[count])) {
> -			igt_info("Highest and lowest mode resolutions are same on output %s; no transition will occur, skipping\n",
> +		if (has_same_dotclock(mode_highres[count], mode_lowres[count])) {
> +			igt_info("Highest and lowest modes have same dotclock on output %s; no CDCLK bump expected, skipping\n",
>   				  igt_output_name(output));
>   			continue;
>   		}