Re: [PATCH i-g-t 2/3] lib/kms: Use for_each_plane_format() for the msm scaler counting

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

On Thu, 16 Apr 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Currently the scaler counting loop iterates over the entire
> format_mod blob format list. That list may contain a lot of duplicate
> formats (one for each modifier supported with that format), so this
> is a bit inefficient. Iterate the plane's format list instead which
> has no duplicates.
>
> Cc: Rob Clark <robdclark@chromium.org>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

I think this is probably fine, but would be nice to get rb from Rob.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>


> ---
>  lib/igt_kms.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/lib/igt_kms.c b/lib/igt_kms.c
> index 2d758b63c043..4cc7c06812c8 100644
> --- a/lib/igt_kms.c
> +++ b/lib/igt_kms.c
> @@ -7504,10 +7504,11 @@ int igt_crtc_num_scalers(igt_crtc_t *crtc)
>  		 * as a rough approximation of the # of scalars.. it may
>  		 * undercount on some hw, but it will not overcount
>  		 */
> -		for_each_plane_on_crtc(crtc,
> -				       plane) {
> -			for (unsigned i = 0; i < plane->format_mod_count; i++) {
> -				if (igt_format_is_yuv(plane->formats[i])) {
> +		for_each_plane_on_crtc(crtc, plane) {
> +			uint32_t format;
> +
> +			for_each_plane_format(plane, format) {
> +				if (igt_format_is_yuv(format)) {
>  					num_scalers++;
>  					break;
>  				}

-- 
Jani Nikula, Intel