[Intel-gfx] [PATCH i-g-t] tests/kms_plane_scaling: Fix off-by-one plane selection

[Gabriel Krisman Bertazi]

Commit ca20170afc6f ("tests/kms_plane_scaling: Add support for dynamic
number of planes") shifted the tested planes by one after the
refactoring, accidentally ignoring the first plane, which is zero
indexed.  A symptom of the issue appears on KBL, where the third plane
is already the shared cursor, causing igt to configure an unsupported
framebuffer format on it, triggering the following error:

[drm:__setplane_internal] Invalid pixel format XR24 little-endian (0x34325258)

With this fixed, we can exposes the pixel clock scaling issue, which is
the actual problem being tracked in Bug 103159, but let's start by
reverting to the old behavior.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103159
Fixes: ca20170afc6f ("tests/kms_plane_scaling: Add support for dynamic number of planes")
Signed-off-by: Gabriel Krisman Bertazi <krisman at collabora.co.uk>
---
 tests/kms_plane_scaling.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/kms_plane_scaling.c b/tests/kms_plane_scaling.c
index 5ed69f35f267..403df47e2d3b 100644
--- a/tests/kms_plane_scaling.c
+++ b/tests/kms_plane_scaling.c
@@ -195,7 +195,7 @@ static void test_plane_scaling(data_t *d)
 		igt_assert(d->fb_id3);
 
 		/* Set up display with plane 1 */
-		d->plane1 = igt_output_get_plane(output, 1);
+		d->plane1 = igt_output_get_plane(output, 0);
 		prepare_crtc(d, output, pipe, d->plane1, mode, COMMIT_UNIVERSAL);
 
 		if (primary_plane_scaling) {
@@ -215,7 +215,7 @@ static void test_plane_scaling(data_t *d)
 		}
 
 		/* Set up fb2->plane2 mapping. */
-		d->plane2 = igt_output_get_plane(output, 2);
+		d->plane2 = igt_output_get_plane(output, 1);
 		igt_plane_set_fb(d->plane2, &d->fb2);
 
 		/* 2nd plane windowed */
@@ -251,7 +251,7 @@ static void test_plane_scaling(data_t *d)
 		}
 
 		/* Set up fb3->plane3 mapping. */
-		d->plane3 = igt_output_get_plane(output, 3);
+		d->plane3 = igt_output_get_plane(output, 2);
 		igt_plane_set_fb(d->plane3, &d->fb3);
 
 		/* 3rd plane windowed - no scaling */
-- 
2.11.0