compositor-drm: Discover atomic properties

Set the atomic client cap, where it exists, and use this to discover the
plane/CRTC/connector properties we require for atomic modesetting.

Differential Revision: https://phabricator.freedesktop.org/D1503

Signed-off-by: Daniel Stone <daniels@collabora.com>
Co-authored-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

2 files changed, 146 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 7a6bb271..be3d7dbe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -206,6 +206,9 @@ AM_CONDITIONAL(ENABLE_DRM_COMPOSITOR, test x$enable_drm_compositor = xyes)
 if test x$enable_drm_compositor = xyes; then
   AC_DEFINE([BUILD_DRM_COMPOSITOR], [1], [Build the DRM compositor])
   PKG_CHECK_MODULES(DRM_COMPOSITOR, [libudev >= 136 libdrm >= 2.4.30 gbm mtdev >= 1.1.0])
+  PKG_CHECK_MODULES(DRM_COMPOSITOR_ATOMIC, [libdrm >= 2.4.62],
+		    [AC_DEFINE([HAVE_DRM_ATOMIC], 1, [libdrm supports atomic API])],
+		    [AC_MSG_WARN([libdrm does not support atomic modesetting, will omit that capability])])
   PKG_CHECK_MODULES(DRM_COMPOSITOR_GBM, [gbm >= 10.2],
 		    [AC_DEFINE([HAVE_GBM_FD_IMPORT], 1, [gbm supports dmabuf import])],
 		    [AC_MSG_WARN([gbm does not support dmabuf import, will omit that capability])])
diff --git a/libweston/compositor-drm.c b/libweston/compositor-drm.c
index 89848bb6..bff4ca50 100644
--- a/libweston/compositor-drm.c
+++ b/libweston/compositor-drm.c
@@ -100,6 +100,16 @@ struct property_item {
  */
 enum wdrm_plane_property {
 	WDRM_PLANE_TYPE = 0,
+	WDRM_PLANE_SRC_X,
+	WDRM_PLANE_SRC_Y,
+	WDRM_PLANE_SRC_W,
+	WDRM_PLANE_SRC_H,
+	WDRM_PLANE_CRTC_X,
+	WDRM_PLANE_CRTC_Y,
+	WDRM_PLANE_CRTC_W,
+	WDRM_PLANE_CRTC_H,
+	WDRM_PLANE_FB_ID,
+	WDRM_PLANE_CRTC_ID,
 	WDRM_PLANE__COUNT
 };
 
@@ -123,6 +133,37 @@ struct plane_properties {
 };
 
 /**
+ * List of properties attached to DRM CRTCs
+ */
+enum wdrm_crtc_property {
+	WDRM_CRTC_MODE_ID = 0,
+	WDRM_CRTC_ACTIVE,
+	WDRM_CRTC__COUNT
+};
+
+/**
+ * List of properties attached to DRM connectors
+ */
+enum wdrm_connector_property {
+	WDRM_CONNECTOR_CRTC_ID = 0,
+	WDRM_CONNECTOR__COUNT
+};
+
+/**
+ * Holding structure for CRTC properties.
+ */
+struct crtc_properties {
+	struct property_item item[WDRM_CRTC__COUNT];
+};
+
+/**
+ * Holding structure for CRTC properties.
+ */
+struct connector_properties {
+	struct property_item item[WDRM_CONNECTOR__COUNT];
+};
+
+/**
  * Mode for drm_output_state_duplicate.
  */
 enum drm_output_state_duplicate_mode {
@@ -171,6 +212,7 @@ struct drm_backend {
 	int cursors_are_broken;
 
 	bool universal_planes;
+	bool atomic_modeset;
 
 	int use_pixman;
 
@@ -300,6 +342,9 @@ struct drm_output {
 	drmModePropertyPtr dpms_prop;
 	uint32_t gbm_format;
 
+	struct crtc_properties props_crtc;
+	struct connector_properties props_conn;
+
 	int vblank_pending;
 	int page_flip_pending;
 	int destroy_pending;
@@ -590,6 +635,16 @@ plane_properties_init(struct drm_plane *plane)
 {
 	static const char * const plane_property_names[] = {
 		[WDRM_PLANE_TYPE] = "type",
+		[WDRM_PLANE_SRC_X] = "SRC_X",
+		[WDRM_PLANE_SRC_Y] = "SRC_Y",
+		[WDRM_PLANE_SRC_W] = "SRC_W",
+		[WDRM_PLANE_SRC_H] = "SRC_H",
+		[WDRM_PLANE_CRTC_X] = "CRTC_X",
+		[WDRM_PLANE_CRTC_Y] = "CRTC_Y",
+		[WDRM_PLANE_CRTC_W] = "CRTC_W",
+		[WDRM_PLANE_CRTC_H] = "CRTC_H",
+		[WDRM_PLANE_FB_ID] = "FB_ID",
+		[WDRM_PLANE_CRTC_ID] = "CRTC_ID",
 	};
 	static const char * const plane_type_names[] = {
 		[WDRM_PLANE_TYPE_PRIMARY] = "Primary",
@@ -682,6 +737,84 @@ drm_plane_get_type(struct drm_plane *plane)
 	return WDRM_PLANE_TYPE_OVERLAY;
 }
 
+/**
+ * Initialise DRM properties for CRTC and connector
+ *
+ * Set up the holding structures to track DRM object properties set on the CRTC
+ * and connector associated with an output.
+ * Free the memory allocated here with output_properties_release.
+ *
+ * @param b DRM backend
+ * @param output Output to configure
+ */
+static bool output_properties_init(struct drm_backend *b,
+				   struct drm_output *output)
+{
+	static const char * const crtc_property_names[] = {
+		[WDRM_CRTC_MODE_ID] = "MODE_ID",
+		[WDRM_CRTC_ACTIVE] = "ACTIVE",
+	};
+	static const char * const connector_property_names[] = {
+		[WDRM_CONNECTOR_CRTC_ID] = "CRTC_ID",
+	};
+	uint32_t valid_mask, required_mask;
+
+	static_assert(ARRAY_LENGTH(crtc_property_names) == WDRM_CRTC__COUNT,
+		      "crtc_property_names mismatch with the enum");
+	static_assert(WDRM_CRTC__COUNT <= 32,
+		      "need more bits for crtc item_valid_mask");
+
+	static_assert(ARRAY_LENGTH(connector_property_names) == WDRM_CONNECTOR__COUNT,
+		      "connector_property_names mismatch with the enum");
+	static_assert(WDRM_CONNECTOR__COUNT <= 32,
+		      "need more bits for connector item_valid_mask");
+
+	valid_mask = drm_properties_get_from_obj(b,
+						 output->props_crtc.item,
+						 crtc_property_names,
+						 WDRM_CRTC__COUNT,
+						 output->crtc_id,
+						 DRM_MODE_OBJECT_CRTC);
+
+	required_mask = 0;
+	if ((valid_mask & required_mask) != required_mask) {
+		weston_log("DRM error: failed to look up all CRTC properties "
+			   "(wanted 0x%x got 0x%x) on ID %d\n",
+			   required_mask, valid_mask, output->crtc_id);
+		return false;
+	}
+
+	valid_mask = drm_properties_get_from_obj(b,
+						 output->props_conn.item,
+						 connector_property_names,
+						 WDRM_CONNECTOR__COUNT,
+						 output->connector_id,
+						 DRM_MODE_OBJECT_CONNECTOR);
+	required_mask = 0;
+	if ((valid_mask & required_mask) != required_mask) {
+		weston_log("DRM error: failed to look up all connector properties "
+			   "(wanted 0x%x got 0x%x) on ID %d\n",
+			   required_mask, valid_mask, output->connector_id);
+		return false;
+	}
+
+	return true;
+}
+
+/**
+ * Free DRM CRTC and connector properties
+ *
+ * The counterpart to output_properties_init.
+ *
+ * @param output Output to release properties for
+ */
+static void output_properties_release(struct drm_output *output)
+{
+	property_item_array_release(output->props_crtc.item, WDRM_CRTC__COUNT);
+	property_item_array_release(output->props_conn.item,
+				    WDRM_CONNECTOR__COUNT);
+}
+
 static void
 drm_output_set_cursor(struct drm_output_state *output_state);
 
@@ -2552,6 +2685,13 @@ init_kms_caps(struct drm_backend *b)
 	weston_log("DRM: %s universal planes\n",
 		   b->universal_planes ? "supports" : "does not support");
 
+#ifdef HAVE_DRM_ATOMIC
+	ret = drmSetClientCap(b->drm.fd, DRM_CLIENT_CAP_ATOMIC, 1);
+	b->atomic_modeset = (ret == 0);
+#endif
+	weston_log("DRM: %s atomic modesetting\n",
+		   b->atomic_modeset ? "supports" : "does not support");
+
 	return 0;
 }
 
@@ -3816,6 +3956,7 @@ drm_output_destroy(struct weston_output *base)
 
 	assert(!output->state_last);
 	drm_output_state_free(output->state_cur);
+	output_properties_release(output);
 	assert(!output->state_pending);
 
 	free(output);
@@ -3899,6 +4040,8 @@ create_output_for_connector(struct drm_backend *b,
 	output->base.name = make_connector_name(connector);
 	output->base.gamma_size = origcrtc->gamma_size;
 
+	output_properties_init(b, output);
+
 	output->destroy_pending = 0;
 	output->disable_pending = 0;