drm/connector: Print connector colorspace in state debugfs

v3: Fix kerneldocs (kernel test robot)

v4: Avoid returning NULL from drm_get_colorspace_name

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Sebastian Wick <sebastian.wick@redhat.com>
Reviewed-by: Joshua Ashton <joshua@froggi.es>
Reviewed-by: Simon Ser <contact@emersion.fr>

Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Sebastian Wick <sebastian.wick@redhat.com>
Cc: Vitaly.Prosyak@amd.com
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joshua Ashton <joshua@froggi.es>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: Melissa Wen <mwen@igalia.com>
Cc: dri-devel@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/drm_atomic.c

@@ -1131,6 +1131,7 @@ static void drm_atomic_connector_print_state(struct drm_printer *p,
 	drm_printf(p, "\tcrtc=%s\n", state->crtc ? state->crtc->name : "(null)");
 	drm_printf(p, "\tself_refresh_aware=%d\n", state->self_refresh_aware);
 	drm_printf(p, "\tmax_requested_bpc=%d\n", state->max_requested_bpc);
+	drm_printf(p, "\tcolorspace=%s\n", drm_get_colorspace_name(state->colorspace));
 
 	if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK)
 		if (state->writeback_job && state->writeback_job->fb)

drivers/gpu/drm/drm_connector.c

@@ -1087,6 +1087,21 @@ static const char * const colorspace_names[] = {
 	[DRM_MODE_COLORIMETRY_BT601_YCC] = "BT601_YCC",
 };
 
+/**
+ * drm_get_colorspace_name - return a string for color encoding
+ * @colorspace: color space to compute name of
+ *
+ * In contrast to the other drm_get_*_name functions this one here returns a
+ * const pointer and hence is threadsafe.
+ */
+const char *drm_get_colorspace_name(enum drm_colorspace colorspace)
+{
+	if (colorspace < ARRAY_SIZE(colorspace_names) && colorspace_names[colorspace])
+		return colorspace_names[colorspace];
+	else
+		return "(null)";
+}
+
 static const u32 hdmi_colorspaces =
 	BIT(DRM_MODE_COLORIMETRY_SMPTE_170M_YCC) |
 	BIT(DRM_MODE_COLORIMETRY_BT709_YCC) |

include/drm/drm_connector.h

@@ -2078,6 +2078,7 @@ void drm_connector_list_iter_end(struct drm_connector_list_iter *iter);
 
 bool drm_connector_has_possible_encoder(struct drm_connector *connector,
 					struct drm_encoder *encoder);
+const char *drm_get_colorspace_name(enum drm_colorspace colorspace);
 
 /**
  * drm_for_each_connector_iter - connector_list iterator macro