Re: [PATCH i-g-t v2] tests/kms: correct index validation logic

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

On Tue, 21 Apr 2026, Jing-Ping Jan <jingpingjan@google.com> wrote:
> Based on the original implementation and the comment above the function,
> it appears the expected behavior is for the plane indices to remain
> consistent with those in crtc->planes. Therefore, after swapping the old
> and new primary planes, we must update the index in igt_plane_t to
> ensure it matches the corresponding index in crtc->planes.
>
> Therefore, we should expect the indices of the old and new primary
> planes to remain unchanged after swapping them.
>
> Fixes: ac37e1174cc4 ("lib/kms: Pimp the primary plane swapping")

With Fixes: it's customary to Cc the author and reviewer(s).

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>

> Signed-off-by: Jing-Ping Jan <jingpingjan@google.com>
> ---
> v2:
>   - Add Fixes tag to the commit message.
>  lib/igt_kms.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/igt_kms.c b/lib/igt_kms.c
> index bec96f267..405a04640 100644
> --- a/lib/igt_kms.c
> +++ b/lib/igt_kms.c
> @@ -2982,8 +2982,8 @@ void igt_display_reset_outputs(igt_display_t *display)

The whole context here is:

			if (new_primary->index != 0) {
				igt_assert(old_primary != new_primary);

				igt_assert_eq(old_primary->index, 0);
				igt_assert_neq(new_primary->index, 0);

>  				igt_swap(*old_primary, *new_primary);
>  				igt_swap(old_primary->index, new_primary->index);
>  
> -				igt_assert_neq(old_primary->index, 0);
> -				igt_assert_eq(new_primary->index, 0);
> +				igt_assert_eq(old_primary->index, 0);
> +				igt_assert_neq(new_primary->index, 0);

Why do you expect these to remain the same as before the swapping?
That's why we are swapping.

>  			} else {
>  				igt_assert(old_primary == new_primary);

-- 
Jani Nikula, Intel