[RFC PATCH v2 09/11] tests/kms_colorop: Keep CRTC active between YUV tests with temp FB

[Harry Wentland <harry.wentland@amd.com>]

Move output_fb creation to fixture and introduce temp_fb to keep the
plane/CRTC active between YUV subtests. This prevents the "framebuffer
without CRTC" error that occurred when removing input_fb caused IGT to
disable the CRTC, leaving the writeback connector detached but with FB
still set.

Each YUV test now:
- Creates input_fb with specific encoding/range
- Runs test
- Switches plane to temp_fb (commits to hardware)
- Removes input_fb safely

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
---
 tests/kms_colorop.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/tests/kms_colorop.c b/tests/kms_colorop.c
index fbf254b694bb..34c3b5d1fe5b 100644
--- a/tests/kms_colorop.c
+++ b/tests/kms_colorop.c
@@ -591,7 +591,7 @@ int igt_main_args("d", long_options, help_str, opt_handler, NULL)
 	for (j = 0; j < ARRAY_SIZE(formats_yuv); j++) {
 		igt_output_t *output;
 		igt_plane_t *plane;
-		igt_fb_t output_fb;
+		igt_fb_t temp_fb, output_fb;
 		unsigned int fb_id;
 		drmModeModeInfo mode;
 
@@ -611,7 +611,14 @@ int igt_main_args("d", long_options, help_str, opt_handler, NULL)
 				igt_assert(plane);
 				igt_require(igt_plane_has_prop(plane, IGT_PLANE_COLOR_PIPELINE));
 
-				/* create output fb */
+				/* Create temp fb to keep plane active between tests */
+				fb_id = igt_create_fb(display.drm_fd, mode.hdisplay, mode.vdisplay,
+							formats_yuv[j].fourcc_in,
+							igt_fb_mod_to_tiling(0),
+							&temp_fb);
+				igt_require(fb_id > 0);
+
+				/* Create output fb shared across tests */
 				fb_id = igt_create_fb(display.drm_fd, mode.hdisplay, mode.vdisplay,
 							formats_yuv[j].fourcc_out,
 							igt_fb_mod_to_tiling(0),
@@ -619,7 +626,7 @@ int igt_main_args("d", long_options, help_str, opt_handler, NULL)
 				igt_require(fb_id > 0);
 			}
 
-			/* Run YUV tests - create input_fb per test with correct encoding/range */
+			/* Run YUV tests - create input_fb per test */
 			for (i = 0; i < ARRAY_SIZE(tests_yuv); i++) {
 				igt_describe("Check YUV CSC colorop");
 				igt_subtest_f("plane-%s-%s", formats_yuv[j].name, tests_yuv[i].name) {
@@ -654,14 +661,20 @@ int igt_main_args("d", long_options, help_str, opt_handler, NULL)
 							formats_yuv[j].fourcc_out,
 							tests_yuv[i].colorops);
 
+					/* Switch plane back to temp_fb to keep CRTC active */
+					igt_plane_set_fb(plane, &temp_fb);
+					igt_display_commit_atomic(&display,
+								DRM_MODE_ATOMIC_ALLOW_MODESET,
+								NULL);
+
 					igt_remove_fb(display.drm_fd, &input_fb);
 				}
 			}
 
 			igt_fixture() {
 				igt_detach_crtc(&display, output);
+				igt_remove_fb(display.drm_fd, &temp_fb);
 				igt_remove_fb(display.drm_fd, &output_fb);
-
 			}
 		}
 	}
-- 
2.53.0