drm: Update docs for legacy kms state

Point at the equivalent atomic state and explain that atomic drivers
shouldn't really depend upon legacy state.

Motivated by questions from Manasi about how this all is supposed to
work.

Cc: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171108203007.12274-1-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 27dc6838533ab7529f86069830a2cc97aa71c471..15cc189ed1a33c24010ef6aa8a192c5a5dd632e8 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -907,6 +907,12 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
  *
  * Drivers can use this for building their own atomic commit if they don't have
  * a pure helper-based modeset implementation.
+ *
+ * Since these updates are not synchronized with lockings, only code paths
+ * called from &drm_mode_config_helper_funcs.atomic_commit_tail can look at the
+ * legacy state filled out by this helper. Defacto this means this helper and
+ * the legacy state pointers are only really useful for transitioning an
+ * existing driver to the atomic world.
  */
 void
 drm_atomic_helper_update_legacy_modeset_state(struct drm_device *dev,

diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index b34904dc8b9beb5ca068b6ebd63ae4cb03a97665..b81b7fb846f9bfca0fc95aec44ed509c328187a0 100644 (file)
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -699,7 +699,6 @@ struct drm_cmdline_mode {
  * @force: a DRM_FORCE_<foo> state for forced mode sets
  * @override_edid: has the EDID been overwritten through debugfs for testing?
  * @encoder_ids: valid encoders for this connector
- * @encoder: encoder driving this connector, if any
  * @eld: EDID-like data, if present
  * @latency_present: AV delay info from ELD, if found
  * @video_latency: video latency info from ELD, if found
@@ -869,7 +868,13 @@ struct drm_connector {
 
 #define DRM_CONNECTOR_MAX_ENCODER 3
        uint32_t encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
-       struct drm_encoder *encoder; /* currently active encoder */
+       /**
+        * @encoder: Currently bound encoder driving this connector, if any.
+        * Only really meaningful for non-atomic drivers. Atomic drivers should
+        * instead look at &drm_connector_state.best_encoder, and in case they
+        * need the CRTC driving this output, &drm_connector_state.crtc.
+        */
+       struct drm_encoder *encoder;
 
 #define MAX_ELD_BYTES  128
        /* EDID bits */

diff --git a/include/drm/drm_encoder.h b/include/drm/drm_encoder.h
index 8d8245ec0181d043324f86ea15b22a63ce12c227..c3ca2278ea6e35e109e73e032a290541d4f335a3 100644 (file)
--- a/include/drm/drm_encoder.h
+++ b/include/drm/drm_encoder.h
@@ -88,7 +88,6 @@ struct drm_encoder_funcs {
  * @head: list management
  * @base: base KMS object
  * @name: human readable name, can be overwritten by the driver
- * @crtc: currently bound CRTC
  * @bridge: bridge associated to the encoder
  * @funcs: control functions
  * @helper_private: mid-layer private data
@@ -166,6 +165,11 @@ struct drm_encoder {
         */
        uint32_t possible_clones;
 
+       /**
+        * @crtc: Currently bound CRTC, only really meaningful for non-atomic
+        * drivers.  Atomic drivers should instead check
+        * &drm_connector_state.crtc.
+        */
        struct drm_crtc *crtc;
        struct drm_bridge *bridge;
        const struct drm_encoder_funcs *funcs;

diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
index 82a217bd77f05a8014f364b0e434ea486e665b61..68bf66473faa626049f353a4101e5d351722331e 100644 (file)
--- a/include/drm/drm_plane.h
+++ b/include/drm/drm_plane.h
@@ -474,8 +474,6 @@ enum drm_plane_type {
  * @format_types: array of formats supported by this plane
  * @format_count: number of formats supported
  * @format_default: driver hasn't supplied supported formats for the plane
- * @crtc: currently bound CRTC
- * @fb: currently bound fb
  * @old_fb: Temporary tracking of the old fb while a modeset is ongoing. Used by
  *     drm_mode_set_config_internal() to implement correct refcounting.
  * @funcs: helper functions
@@ -512,7 +510,17 @@ struct drm_plane {
        uint64_t *modifiers;
        unsigned int modifier_count;
 
+       /**
+        * @crtc: Currently bound CRTC, only really meaningful for non-atomic
+        * drivers.  Atomic drivers should instead check &drm_plane_state.crtc.
+        */
        struct drm_crtc *crtc;
+
+       /**
+        * @fb: Currently bound framebuffer, only really meaningful for
+        * non-atomic drivers.  Atomic drivers should instead check
+        * &drm_plane_state.fb.
+        */
        struct drm_framebuffer *fb;
 
        struct drm_framebuffer *old_fb;