tests/kms_dither: Skip if current & requested BPC doesn't match

The "max bpc" property only ensures that the bpc will not go beyond
the value set through this property. It does not guarantee that the
same bpc will be used for the given mode.

If clock/bandwidth constraints permit, the max bpc will be used to
show the mode, otherwise the bpc will be reduced. So, if we really
want a particular bpc set, we can try reducing the resolution, till
we get the bpc that we set in max bpc property.

This patch will skip the test, if there is no valid resolution to get
the same bpc as set by max_bpc property.

Cc: Swati Sharma <swati2.sharma@intel.com>
CC: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>

1 files changed, 37 insertions, 35 deletions

diff --git a/tests/kms_dither.c b/tests/kms_dither.c
index c72f83be..02896b37 100644
--- a/tests/kms_dither.c
+++ b/tests/kms_dither.c
@@ -46,10 +46,6 @@ IGT_TEST_DESCRIPTION("Test Dithering block status");
 typedef struct data {
 	igt_display_t display;
 	igt_plane_t *primary;
-	igt_output_t *output;
-	igt_pipe_t *pipe;
-	drmModeModeInfo *mode;
-	enum pipe pipe_id;
 	int drm_fd;
 	igt_fb_t fb;
 } data_t;
@@ -60,30 +56,23 @@ typedef struct {
 } dither_status_t;
 
 /* Prepare test data. */
-static void prepare_test(data_t *data, igt_output_t *output, enum pipe pipe)
+static void prepare_test(data_t *data, igt_output_t *output, enum pipe p)
 {
 	igt_display_t *display = &data->display;
+	igt_pipe_t *pipe = &data->display.pipes[p];
 
-	data->pipe_id = pipe;
-	data->pipe = &data->display.pipes[data->pipe_id];
-	igt_assert(data->pipe);
+	igt_assert(pipe);
 
 	igt_display_reset(display);
 
-	data->output = output;
-	igt_assert(data->output);
-
-	data->mode = igt_output_get_mode(data->output);
-	igt_assert(data->mode);
-
 	data->primary =
-		igt_pipe_get_plane_type(data->pipe, DRM_PLANE_TYPE_PRIMARY);
+		igt_pipe_get_plane_type(pipe, DRM_PLANE_TYPE_PRIMARY);
 
-	igt_output_set_pipe(data->output, data->pipe_id);
+	igt_output_set_pipe(output, p);
 }
 
 /* Returns the current state of dithering from the crtc debugfs. */
-static dither_status_t get_dither_state(data_t *data)
+static dither_status_t get_dither_state(data_t *data, enum pipe pipe)
 {
 	char buf[512], tmp[5];
 	char *start_loc;
@@ -103,11 +92,34 @@ static dither_status_t get_dither_state(data_t *data)
 	igt_assert_eq(sscanf(start_loc, ", dither=%s", tmp), 1);
 	status.dither = !strcmp(tmp, "yes,");
 
-	status.bpc = igt_get_pipe_current_bpc(data->drm_fd, data->pipe_id);
+	status.bpc = igt_get_pipe_current_bpc(data->drm_fd, pipe);
 
 	return status;
 }
 
+static bool i915_clock_constraint(data_t *data, enum pipe pipe,
+				  igt_output_t *output, int bpc)
+{
+	drmModeConnector *connector = output->config.connector;
+	igt_display_t *display = &data->display;
+
+	igt_sort_connector_modes(connector, sort_drm_modes_by_clk_dsc);
+
+	for_each_connector_mode(output) {
+		igt_output_override_mode(output, &connector->modes[j__]);
+		igt_display_commit2(display, display->is_atomic ? COMMIT_ATOMIC : COMMIT_LEGACY);
+
+		if (!igt_check_output_bpc_equal(data->drm_fd, pipe,
+						output->name, bpc))
+			continue;
+
+		return true;
+	}
+
+	igt_output_override_mode(output, NULL);
+	return false;
+}
+
 static void test_dithering(data_t *data, enum pipe pipe,
 			   igt_output_t *output,
 			   int fb_bpc, int fb_format,
@@ -121,14 +133,12 @@ static void test_dithering(data_t *data, enum pipe pipe,
 			output->name, kmstest_pipe_name(pipe));
 	prepare_test(data, output, pipe);
 
-	igt_assert(igt_create_fb(data->drm_fd, data->mode->hdisplay,
-				 data->mode->vdisplay, fb_format,
+	igt_assert(igt_create_fb(data->drm_fd, 512, 512, fb_format,
 				 DRM_FORMAT_MOD_LINEAR, &data->fb));
 	igt_plane_set_fb(data->primary, &data->fb);
-	igt_plane_set_size(data->primary, data->mode->hdisplay, data->mode->vdisplay);
 
 	bpc = igt_output_get_prop(output, IGT_CONNECTOR_MAX_BPC);
-	igt_output_set_prop_value(data->output, IGT_CONNECTOR_MAX_BPC, output_bpc);
+	igt_output_set_prop_value(output, IGT_CONNECTOR_MAX_BPC, output_bpc);
 
 	if (display->is_atomic)
 		ret = igt_display_try_commit_atomic(display,
@@ -141,12 +151,9 @@ static void test_dithering(data_t *data, enum pipe pipe,
 	igt_require_f(!ret, "%s don't support %d-bpc\n",
 				output->name, output_bpc);
 
-	igt_display_commit2(display, display->is_atomic ? COMMIT_ATOMIC : COMMIT_LEGACY);
-
-	if (!igt_check_output_bpc_equal(data->drm_fd, pipe, output->name, output_bpc)) {
-		igt_output_set_prop_value(output, IGT_CONNECTOR_MAX_BPC, bpc);
-		igt_fail_on_f(true, "Failed to set max_bpc as: %d\n", output_bpc);
-	}
+	igt_require_f(i915_clock_constraint(data, pipe, output, output_bpc),
+			"No supported mode found to use %d-bpc on %s\n",
+			output_bpc, output->name);
 
 	/*
 	 * Check the status of Dithering block:
@@ -155,7 +162,7 @@ static void test_dithering(data_t *data, enum pipe pipe,
 	 * If fb_bpc is greater than output_bpc, Dithering should be enabled
 	 * Else disabled
 	 */
-	status = get_dither_state(data);
+	status = get_dither_state(data, pipe);
 
 	igt_info("FB BPC:%d, Panel BPC:%d, Pipe BPC:%d, Expected Dither:%s, Actual result:%s\n",
 		  fb_bpc, output_bpc, status.bpc,
@@ -167,17 +174,12 @@ static void test_dithering(data_t *data, enum pipe pipe,
 	* Otherwise, previously updated value will stay forever and
 	* may cause the failures for next/other subtests.
 	*/
-	igt_output_set_prop_value(data->output, IGT_CONNECTOR_MAX_BPC, bpc);
+	igt_output_set_prop_value(output, IGT_CONNECTOR_MAX_BPC, bpc);
 	igt_plane_set_fb(data->primary, NULL);
 	igt_output_set_pipe(output, PIPE_NONE);
 	igt_display_commit2(display, display->is_atomic ? COMMIT_ATOMIC : COMMIT_LEGACY);
 	igt_remove_fb(data->drm_fd, &data->fb);
 
-	/* Check if crtc bpc is updated with requested one. */
-	igt_require_f((status.bpc == output_bpc),
-			"%s can support max %u-bpc, but requested %d-bpc\n",
-				output->name, status.bpc, output_bpc);
-
 	/* Compute the result. */
 	if (fb_bpc > output_bpc)
 		igt_assert_f(status.dither, "(fb_%dbpc > output_%dbpc): Dither should be enabled\n",