drm: Refuse to async flip with atomic prop changes

Given that prop changes may lead to modesetting, which would defeat the
fast path of the async flip, refuse any atomic prop change for async
flips in atomic API. The only exception is the framebuffer ID to flip
to. Currently the only plane type supported is the primary one.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patchwork.freedesktop.org/patch/msgid/20231122161941.320564-2-andrealmeid@igalia.com

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index 98d3b10c08ae194071777b4abb2ed8c2e43286a5..52494642b095c7ecd1ca1daca6076d10ebf7f75a 100644 (file)
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -1006,13 +1006,28 @@ out:
        return ret;
 }
 
+static int drm_atomic_check_prop_changes(int ret, uint64_t old_val, uint64_t prop_value,
+                                        struct drm_property *prop)
+{
+       if (ret != 0 || old_val != prop_value) {
+               drm_dbg_atomic(prop->dev,
+                              "[PROP:%d:%s] No prop can be changed during async flip\n",
+                              prop->base.id, prop->name);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
 int drm_atomic_set_property(struct drm_atomic_state *state,
                            struct drm_file *file_priv,
                            struct drm_mode_object *obj,
                            struct drm_property *prop,
-                           uint64_t prop_value)
+                           u64 prop_value,
+                           bool async_flip)
 {
        struct drm_mode_object *ref;
+       u64 old_val;
        int ret;
 
        if (!drm_property_change_valid_get(prop, prop_value, &ref))
@@ -1029,6 +1044,13 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
                        break;
                }
 
+               if (async_flip) {
+                       ret = drm_atomic_connector_get_property(connector, connector_state,
+                                                               prop, &old_val);
+                       ret = drm_atomic_check_prop_changes(ret, old_val, prop_value, prop);
+                       break;
+               }
+
                ret = drm_atomic_connector_set_property(connector,
                                connector_state, file_priv,
                                prop, prop_value);
@@ -1044,6 +1066,13 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
                        break;
                }
 
+               if (async_flip) {
+                       ret = drm_atomic_crtc_get_property(crtc, crtc_state,
+                                                          prop, &old_val);
+                       ret = drm_atomic_check_prop_changes(ret, old_val, prop_value, prop);
+                       break;
+               }
+
                ret = drm_atomic_crtc_set_property(crtc,
                                crtc_state, prop, prop_value);
                break;
@@ -1051,6 +1080,7 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
        case DRM_MODE_OBJECT_PLANE: {
                struct drm_plane *plane = obj_to_plane(obj);
                struct drm_plane_state *plane_state;
+               struct drm_mode_config *config = &plane->dev->mode_config;
 
                plane_state = drm_atomic_get_plane_state(state, plane);
                if (IS_ERR(plane_state)) {
@@ -1058,6 +1088,21 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
                        break;
                }
 
+               if (async_flip && prop != config->prop_fb_id) {
+                       ret = drm_atomic_plane_get_property(plane, plane_state,
+                                                           prop, &old_val);
+                       ret = drm_atomic_check_prop_changes(ret, old_val, prop_value, prop);
+                       break;
+               }
+
+               if (async_flip && plane_state->plane->type != DRM_PLANE_TYPE_PRIMARY) {
+                       drm_dbg_atomic(prop->dev,
+                                      "[OBJECT:%d] Only primary planes can be changed during async flip\n",
+                                      obj->id);
+                       ret = -EINVAL;
+                       break;
+               }
+
                ret = drm_atomic_plane_set_property(plane,
                                plane_state, file_priv,
                                prop, prop_value);
@@ -1337,6 +1382,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
        struct drm_out_fence_state *fence_state;
        int ret = 0;
        unsigned int i, j, num_fences;
+       bool async_flip = false;
 
        /* disallow for drivers not supporting atomic: */
        if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
@@ -1450,8 +1496,8 @@ retry:
                                goto out;
                        }
 
-                       ret = drm_atomic_set_property(state, file_priv,
-                                                     obj, prop, prop_value);
+                       ret = drm_atomic_set_property(state, file_priv, obj,
+                                                     prop, prop_value, async_flip);
                        if (ret) {
                                drm_mode_object_put(obj);
                                goto out;

diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
index 6b646e0783be9626dbbde60900b2bd2b94621d18..a514d5207e4197ac6434fbfeb9fb3a4bfe0d771e 100644 (file)
--- a/drivers/gpu/drm/drm_crtc_internal.h
+++ b/drivers/gpu/drm/drm_crtc_internal.h
@@ -253,7 +253,7 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
                            struct drm_file *file_priv,
                            struct drm_mode_object *obj,
                            struct drm_property *prop,
-                           uint64_t prop_value);
+                           u64 prop_value, bool async_flip);
 int drm_atomic_get_property(struct drm_mode_object *obj,
                            struct drm_property *property, uint64_t *val);
 

diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c
index ac0d2ce3f870411b3a31495bfdcfa16f7e82705c..0e8355063eee36a7d9166fc6c5ccc26a279dcb86 100644 (file)
--- a/drivers/gpu/drm/drm_mode_object.c
+++ b/drivers/gpu/drm/drm_mode_object.c
@@ -538,7 +538,7 @@ retry:
                                                       obj_to_connector(obj),
                                                       prop_value);
        } else {
-               ret = drm_atomic_set_property(state, file_priv, obj, prop, prop_value);
+               ret = drm_atomic_set_property(state, file_priv, obj, prop, prop_value, false);
                if (ret)
                        goto out;
                ret = drm_atomic_commit(state);