This is RFC patch for adding a connector link-status property
and making it atomic by adding it to the drm_connector_state.
This is to make sure its wired properly in drm_atomic_connector_set_property
and drm_atomic_connector_get_property functions.
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
---
drivers/gpu/drm/drm_atomic.c | 5 ++++
drivers/gpu/drm/drm_connector.c | 65 +++++++++++++++++++++++++++++++++++++++--
include/drm/drm_connector.h | 12 +++++++-
include/drm/drm_mode_config.h | 5 ++++
include/uapi/drm/drm_mode.h | 4 +++
5 files changed, 88 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 89737e4..644d19f 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1087,6 +1087,9 @@ 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) {
+ 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 +1138,8 @@ 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);
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 5a45262..4576c9f 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -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
@@ -616,7 +626,7 @@ int drm_display_info_set_bus_formats(struct drm_display_info *info,
* path property the MST manager created. Userspace cannot change this
* property.
* TILE:
- * Connector tile group property to indicate how a set of DRM connector
+ * Connector tile group property to indicate how a set of DRM connector
* compose together into one logical screen. This is used by both high-res
* external screens (often only using a single cable, but exposing multiple
* DP MST sinks), or high-res integrated panels (like dual-link DSI) which
@@ -625,7 +635,14 @@ 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 during
+ * the modeset. The default value of link-status is "GOOD". If something
+ * fails during modeset, the kernel driver can set this to "BAD", prune
+ * the mode list based on new link parameters and send a hotplug uevent
+ * to notify userspace to re-check the valid modes through GET_CONNECTOR
+ * IOCTL and redo a modeset. Drivers should update this value using
+ * drm_mode_connector_set_link_status_property().
* Connectors also have one standardized atomic property:
*
* CRTC_ID:
@@ -666,6 +683,13 @@ int drm_connector_create_standard_properties(struct drm_device *dev)
return -ENOMEM;
dev->mode_config.tile_property = prop;
+ prop = drm_property_create_enum(dev, DRM_MODE_PROP_ATOMIC, "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 +1019,43 @@ 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 should
+ * set this link status property to "BAD" and prune the mode list based on new
+ * information. 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 that a lot of existing userspace do not handle this property.
+ * Drivers can therefore not rely on userspace to fix up everything and
+ * should try to handle issues (like just re-training a link) without
+ * userspace's intervention. This should only be used when the current mode
+ * fails and userspace must select a different display mode.
+ * The DRM driver can chose to not modify property and keep link status
+ * as "GOOD" always to keep the user experience same as it currently is.
+ *
+ * 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;
+
+ /* Make sure the mutex is grabbed */
+ lockdep_assert_held(&dev->mode_config.mutex);
+ connector->link_status = link_status;
+ drm_object_property_set_value(&connector->base,
+ dev->mode_config.link_status_property,
+ link_status);
+}
+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)
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 34f9741..3d513ab 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -213,6 +213,9 @@ struct drm_connector_state {
struct drm_encoder *best_encoder;
+ /* Connector Link status */
+ unsigned int link_status;
+
struct drm_atomic_state *state;
};
@@ -695,6 +698,12 @@ struct drm_connector {
uint8_t num_h_tile, num_v_tile;
uint8_t tile_h_loc, tile_v_loc;
uint16_t tile_h_size, tile_v_size;
+
+ /* Connector Link status
+ * 0: If the link is Good
+ * 1: If the link is Bad
+ */
+ int link_status;
};
#define obj_to_connector(x) container_of(x, struct drm_connector, base)
@@ -767,12 +776,13 @@ int drm_mode_create_tv_properties(struct drm_device *dev,
int drm_mode_create_scaling_mode_property(struct drm_device *dev);
int drm_mode_create_aspect_ratio_property(struct drm_device *dev);
int drm_mode_create_suggested_offset_properties(struct drm_device *dev);
-
int drm_mode_connector_set_path_property(struct drm_connector *connector,
const char *path);
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
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index bf9991b..86faee4 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -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.
*/
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 728790b..309c478 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -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;
--
1.9.1
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