@@ -1087,6 +1087,22 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
* now?) atomic writes to DPMS property:
*/
return -EINVAL;
+ } else if (property == config->link_status_property) {
+ /* Never downgrade from GOOD to BAD on userspace's request here,
+ * only hw issues can do that.
+ *
+ * For an atomic property the userspace doesn't need to be able
+ * to understand all the properties, but needs to be able to
+ * restore the state itw ants on VT switch. So if the userspace
+ * tries to change the link_status from GOOD to BAD, driver
+ * silently rejects it and returns a 0. This prevents userspace
+ * from accidently breaking the display when it restores the
+ * state.
+ */
+ if (state->link_status == DRM_LINK_STATUS_GOOD)
+ return 0;
+ state->link_status = val;
+ return 0;
} else if (connector->funcs->atomic_set_property) {
return connector->funcs->atomic_set_property(connector,
state, property, val);
@@ -1135,6 +1151,8 @@ static void drm_atomic_connector_print_state(struct drm_printer *p,
*val = (state->crtc) ? state->crtc->base.id : 0;
} else if (property == config->dpms_property) {
*val = connector->dpms;
+ } else if (property == config->link_status_property) {
+ *val = state->link_status;
} else if (connector->funcs->atomic_get_property) {
return connector->funcs->atomic_get_property(connector,
state, property, val);
@@ -519,6 +519,13 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
connector_state);
if (ret)
return ret;
+ if (connector->state->crtc) {
+ crtc_state = drm_atomic_get_existing_crtc_state(state,
+ connector->state->crtc);
+ if (connector->state->link_status !=
+ connector_state->link_status)
+ crtc_state->connectors_changed = true;
+ }
}
/*
@@ -2255,6 +2262,8 @@ static int update_output_state(struct drm_atomic_state *state,
NULL);
if (ret)
return ret;
+ /* Make sure legacy setCrtc always re-trains */
+ conn_state->link_status = DRM_LINK_STATUS_GOOD;
}
}
@@ -2298,6 +2307,12 @@ static int update_output_state(struct drm_atomic_state *state,
*
* Provides a default crtc set_config handler using the atomic driver interface.
*
+ * NOTE: For backwards compatibility with old userspace this automatically
+ * resets the "link-status" property to GOOD, to force any link
+ * re-training. The SETCRTC ioctl does not define whether an update does
+ * need a full modeset or just a plane update, hence we're allowed to do
+ * that. See also drm_mode_connector_set_link_status_property().
+ *
* Returns:
* Returns 0 on success, negative errno numbers on failure.
*/
@@ -243,6 +243,10 @@ int drm_connector_init(struct drm_device *dev,
drm_object_attach_property(&connector->base,
config->dpms_property, 0);
+ drm_object_attach_property(&connector->base,
+ config->link_status_property,
+ 0);
+
if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
drm_object_attach_property(&connector->base, config->prop_crtc_id, 0);
}
@@ -506,6 +510,12 @@ const char *drm_get_subpixel_order_name(enum subpixel_order order)
};
DRM_ENUM_NAME_FN(drm_get_dpms_name, drm_dpms_enum_list)
+static const struct drm_prop_enum_list drm_link_status_enum_list[] = {
+ { DRM_MODE_LINK_STATUS_GOOD, "Good" },
+ { DRM_MODE_LINK_STATUS_BAD, "Bad" },
+};
+DRM_ENUM_NAME_FN(drm_get_link_status_name, drm_link_status_enum_list)
+
/**
* drm_display_info_set_bus_formats - set the supported bus formats
* @info: display info to store bus formats in
@@ -625,6 +635,11 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
* tiling and virtualize both &drm_crtc and &drm_plane if needed. Drivers
* should update this value using drm_mode_connector_set_tile_property().
* Userspace cannot change this property.
+ * link-status:
+ * Connector link-status property to indicate the status of link. The default
+ * value of link-status is "GOOD". If something fails during or after modeset,
+ * the kernel driver may set this to "BAD" and issue a hotplug uevent. Drivers
+ * should update this value using drm_mode_connector_set_link_status_property().
*
* Connectors also have one standardized atomic property:
*
@@ -666,6 +681,13 @@ int drm_connector_create_standard_properties(struct drm_device *dev)
return -ENOMEM;
dev->mode_config.tile_property = prop;
+ prop = drm_property_create_enum(dev, 0, "link-status",
+ drm_link_status_enum_list,
+ ARRAY_SIZE(drm_link_status_enum_list));
+ if (!prop)
+ return -ENOMEM;
+ dev->mode_config.link_status_property = prop;
+
return 0;
}
@@ -995,6 +1017,37 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
}
EXPORT_SYMBOL(drm_mode_connector_update_edid_property);
+/**
+ * drm_mode_connector_set_link_status_property - Set link status property of a connector
+ * @connector: drm connector
+ * @link_status: new value of link status property (0: Good, 1: Bad)
+ *
+ * In usual working scenario, this link status property will always be set to
+ * "GOOD". If something fails during or after a mode set, the kernel driver
+ * may set this link status property to "BAD". The caller then needs to send a
+ * hotplug uevent for userspace to re-check the valid modes through
+ * GET_CONNECTOR_IOCTL and retry modeset.
+ *
+ * Note: Drivers cannot rely on userspace to support this property and
+ * issue a modeset. As such, they may choose to handle issues (like
+ * re-training a link) without userspace's intervention.
+ *
+ * The reason for adding this property is to handle link training failures, but
+ * it is not limited to DP or link training. For example, if we implement
+ * asynchronous setcrtc, this property can be used to report any failures in that.
+ */
+void drm_mode_connector_set_link_status_property(struct drm_connector *connector,
+ uint64_t link_status)
+{
+ struct drm_device *dev = connector->dev;
+
+ drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+ connector->state->link_status = link_status;
+ drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+}
+EXPORT_SYMBOL(drm_mode_connector_set_link_status_property);
+
int drm_mode_connector_set_obj_prop(struct drm_mode_object *obj,
struct drm_property *property,
uint64_t value)
@@ -90,6 +90,17 @@ enum subpixel_order {
};
/**
+ * enum drm_link_status - connector's link_status property value
+ *
+ * This enum is used as the connector's link status property value.
+ * It is set to the values defined in uapi.
+ */
+enum drm_link_status {
+ DRM_LINK_STATUS_GOOD = DRM_MODE_LINK_STATUS_GOOD,
+ DRM_LINK_STATUS_BAD = DRM_MODE_LINK_STATUS_BAD,
+};
+
+/**
* struct drm_display_info - runtime data about the connected sink
*
* Describes a given display (e.g. CRT or flat panel) and its limitations. For
@@ -213,6 +224,12 @@ struct drm_connector_state {
struct drm_encoder *best_encoder;
+ /**
+ * @link_status: Connector link_status to keep track of whether link is
+ * GOOD or BAD to notify userspace if retraining is necessary.
+ */
+ enum drm_link_status link_status;
+
struct drm_atomic_state *state;
};
@@ -776,6 +793,8 @@ int drm_mode_connector_set_path_property(struct drm_connector *connector,
int drm_mode_connector_set_tile_property(struct drm_connector *connector);
int drm_mode_connector_update_edid_property(struct drm_connector *connector,
const struct edid *edid);
+void drm_mode_connector_set_link_status_property(struct drm_connector *connector,
+ uint64_t link_status);
/**
* struct drm_tile_group - Tile group metadata
@@ -431,6 +431,11 @@ struct drm_mode_config {
*/
struct drm_property *tile_property;
/**
+ * @link_status_property: Default connector property for link status
+ * of a connector
+ */
+ struct drm_property *link_status_property;
+ /**
* @plane_type_property: Default plane property to differentiate
* CURSOR, PRIMARY and OVERLAY legacy uses of planes.
*/
@@ -123,6 +123,10 @@
#define DRM_MODE_DIRTY_ON 1
#define DRM_MODE_DIRTY_ANNOTATE 2
+/* Link Status options */
+#define DRM_MODE_LINK_STATUS_GOOD 0
+#define DRM_MODE_LINK_STATUS_BAD 1
+
struct drm_mode_modeinfo {
__u32 clock;
__u16 hdisplay;