diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 3cf1aa132778dafc7ce4aaf4001eedc989e2ebc9..4225b1ca407beffeafa1495f53baa265030e9de5 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -308,6 +308,26 @@ update_connector_routing(struct drm_atomic_state *state,
return 0;
}
+ crtc_state = drm_atomic_get_new_crtc_state(state,
+ new_connector_state->crtc);
+ /*
+ * For compatibility with legacy users, we want to make sure that
+ * we allow DPMS On->Off modesets on unregistered connectors. Modesets
+ * which would result in anything else must be considered invalid, to
+ * avoid turning on new displays on dead connectors.
+ *
+ * Since the connector can be unregistered at any point during an
+ * atomic check or commit, this is racy. But that's OK: all we care
+ * about is ensuring that userspace can't do anything but shut off the
+ * display on a connector that was destroyed after its been notified,
+ * not before.
+ */
+ if (drm_connector_is_unregistered(connector) && crtc_state->active) {
+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] is not registered\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+
funcs = connector->helper_private;
if (funcs->atomic_best_encoder)
@@ -352,7 +372,6 @@ update_connector_routing(struct drm_atomic_state *state,
set_best_encoder(state, new_connector_state, new_encoder);
- crtc_state = drm_atomic_get_new_crtc_state(state, new_connector_state->crtc);
crtc_state->connectors_changed = true;
DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] using [ENCODER:%d:%s] on [CRTC:%d:%s]\n",
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index a22d6f269b07f4a874ca4381f0571b0fd1904733..d5b7f315098c23b2ddc0c0ab74e410396e0ad917 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -299,27 +299,6 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
struct drm_connector *connector = conn_state->connector;
struct drm_crtc_state *crtc_state;
- /*
- * For compatibility with legacy users, we want to make sure that
- * we allow DPMS On<->Off modesets on unregistered connectors, since
- * legacy modesetting users will not be expecting these to fail. We do
- * not however, want to allow legacy users to assign a connector
- * that's been unregistered from sysfs to another CRTC, since doing
- * this with a now non-existent connector could potentially leave us
- * in an invalid state.
- *
- * Since the connector can be unregistered at any point during an
- * atomic check or commit, this is racy. But that's OK: all we care
- * about is ensuring that userspace can't use this connector for new
- * configurations after it's been notified that the connector is no
- * longer present.
- */
- if (!READ_ONCE(connector->registered) && crtc) {
- DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] is not registered\n",
- connector->base.id, connector->name);
- return -EINVAL;
- }
-
if (conn_state->crtc == crtc)
return 0;
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 1e40e5decbe91a4f709305d5259b5b7c0425e617..4943cef178beb7675ab46a0d3100e33ae836bd0e 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -379,7 +379,8 @@ void drm_connector_cleanup(struct drm_connector *connector)
/* The connector should have been removed from userspace long before
* it is finally destroyed.
*/
- if (WARN_ON(connector->registered))
+ if (WARN_ON(connector->registration_state ==
+ DRM_CONNECTOR_REGISTERED))
drm_connector_unregister(connector);
if (connector->tile_group) {
@@ -436,7 +437,7 @@ int drm_connector_register(struct drm_connector *connector)
return 0;
mutex_lock(&connector->mutex);
- if (connector->registered)
+ if (connector->registration_state != DRM_CONNECTOR_INITIALIZING)
goto unlock;
ret = drm_sysfs_connector_add(connector);
@@ -456,7 +457,7 @@ int drm_connector_register(struct drm_connector *connector)
drm_mode_object_register(connector->dev, &connector->base);
- connector->registered = true;
+ connector->registration_state = DRM_CONNECTOR_REGISTERED;
goto unlock;
err_debugfs:
@@ -478,7 +479,7 @@ EXPORT_SYMBOL(drm_connector_register);
void drm_connector_unregister(struct drm_connector *connector)
{
mutex_lock(&connector->mutex);
- if (!connector->registered) {
+ if (connector->registration_state != DRM_CONNECTOR_REGISTERED) {
mutex_unlock(&connector->mutex);
return;
}
@@ -489,7 +490,7 @@ void drm_connector_unregister(struct drm_connector *connector)
drm_sysfs_connector_remove(connector);
drm_debugfs_connector_remove(connector);
- connector->registered = false;
+ connector->registration_state = DRM_CONNECTOR_UNREGISTERED;
mutex_unlock(&connector->mutex);
}
EXPORT_SYMBOL(drm_connector_unregister);
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index b268bdd71bd3ca4da6c504363bc9efd377625166..8b71d64ebd9d42c6329ce6f37882f531d5ef68b3 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -78,7 +78,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
pipe_config->pbn = mst_pbn;
/* Zombie connectors can't have VCPI slots */
- if (READ_ONCE(connector->registered)) {
+ if (!drm_connector_is_unregistered(connector)) {
slots = drm_dp_atomic_find_vcpi_slots(state,
&intel_dp->mst_mgr,
port,
@@ -314,7 +314,7 @@ static int intel_dp_mst_get_ddc_modes(struct drm_connector *connector)
struct edid *edid;
int ret;
- if (!READ_ONCE(connector->registered))
+ if (drm_connector_is_unregistered(connector))
return intel_connector_update_modes(connector, NULL);
edid = drm_dp_mst_get_edid(connector, &intel_dp->mst_mgr, intel_connector->port);
@@ -330,7 +330,7 @@ intel_dp_mst_detect(struct drm_connector *connector, bool force)
struct intel_connector *intel_connector = to_intel_connector(connector);
struct intel_dp *intel_dp = intel_connector->mst_port;
- if (!READ_ONCE(connector->registered))
+ if (drm_connector_is_unregistered(connector))
return connector_status_disconnected;
return drm_dp_mst_detect_port(connector, &intel_dp->mst_mgr,
intel_connector->port);
@@ -361,7 +361,7 @@ intel_dp_mst_mode_valid(struct drm_connector *connector,
int bpp = 24; /* MST uses fixed bpp */
int max_rate, mode_rate, max_lanes, max_link_clock;
- if (!READ_ONCE(connector->registered))
+ if (drm_connector_is_unregistered(connector))
return MODE_ERROR;
if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 91a877fa00cb59161125a711515931e49b040e53..9ccad6b062f2bb62c54434288e7fc9a25b194b53 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -82,6 +82,53 @@ enum drm_connector_status {
connector_status_unknown = 3,
};
+/**
+ * enum drm_connector_registration_status - userspace registration status for
+ * a &drm_connector
+ *
+ * This enum is used to track the status of initializing a connector and
+ * registering it with userspace, so that DRM can prevent bogus modesets on
+ * connectors that no longer exist.
+ */
+enum drm_connector_registration_state {
+ /**
+ * @DRM_CONNECTOR_INITIALIZING: The connector has just been created,
+ * but has yet to be exposed to userspace. There should be no
+ * additional restrictions to how the state of this connector may be
+ * modified.
+ */
+ DRM_CONNECTOR_INITIALIZING = 0,
+
+ /**
+ * @DRM_CONNECTOR_REGISTERED: The connector has been fully initialized
+ * and registered with sysfs, as such it has been exposed to
+ * userspace. There should be no additional restrictions to how the
+ * state of this connector may be modified.
+ */
+ DRM_CONNECTOR_REGISTERED = 1,
+
+ /**
+ * @DRM_CONNECTOR_UNREGISTERED: The connector has either been exposed
+ * to userspace and has since been unregistered and removed from
+ * userspace, or the connector was unregistered before it had a chance
+ * to be exposed to userspace (e.g. still in the
+ * @DRM_CONNECTOR_INITIALIZING state). When a connector is
+ * unregistered, there are additional restrictions to how its state
+ * may be modified:
+ *
+ * - An unregistered connector may only have its DPMS changed from
+ * On->Off. Once DPMS is changed to Off, it may not be switched back
+ * to On.
+ * - Modesets are not allowed on unregistered connectors, unless they
+ * would result in disabling its assigned CRTCs. This means
+ * disabling a CRTC on an unregistered connector is OK, but enabling
+ * one is not.
+ * - Removing a CRTC from an unregistered connector is OK, but new
+ * CRTCs may never be assigned to an unregistered connector.
+ */
+ DRM_CONNECTOR_UNREGISTERED = 2,
+};
+
enum subpixel_order {
SubPixelUnknown = 0,
SubPixelHorizontalRGB,
@@ -853,10 +900,12 @@ struct drm_connector {
bool ycbcr_420_allowed;
/**
- * @registered: Is this connector exposed (registered) with userspace?
+ * @registration_state: Is this connector initializing, exposed
+ * (registered) with userspace, or unregistered?
+ *
* Protected by @mutex.
*/
- bool registered;
+ enum drm_connector_registration_state registration_state;
/**
* @modes:
@@ -1166,6 +1215,24 @@ static inline void drm_connector_unreference(struct drm_connector *connector)
drm_connector_put(connector);
}
+/**
+ * drm_connector_is_unregistered - has the connector been unregistered from
+ * userspace?
+ * @connector: DRM connector
+ *
+ * Checks whether or not @connector has been unregistered from userspace.
+ *
+ * Returns:
+ * True if the connector was unregistered, false if the connector is
+ * registered or has not yet been registered with userspace.
+ */
+static inline bool
+drm_connector_is_unregistered(struct drm_connector *connector)
+{
+ return READ_ONCE(connector->registration_state) ==
+ DRM_CONNECTOR_UNREGISTERED;
+}
+
const char *drm_get_connector_status_name(enum drm_connector_status status);
const char *drm_get_subpixel_order_name(enum subpixel_order order);
const char *drm_get_dpms_name(int val);