Due to the fact that writeback connectors behave in a special way
in DRM (they always report being disconnected) we might confuse some
userspace. Add a client capability for writeback connectors that will
filter them out for clients that don't understand the capability.
Re-requested-by: Sean Paul <seanp...@chromium.org>
Cc: Brian Starkey <brian.star...@arm.com>
Signed-off-by: Liviu Dudau <liviu.du...@arm.com>
---
drivers/gpu/drm/drm_ioctl.c | 7 +++++++
drivers/gpu/drm/drm_mode_config.c | 5 +++++
include/drm/drm_file.h | 7 +++++++
include/uapi/drm/drm.h | 9 +++++++++
4 files changed, 28 insertions(+)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index af782911c505d..59951ff3e3630 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -325,6 +325,13 @@ drm_setclientcap(struct drm_device *dev, void *data,
struct drm_file *file_priv)
file_priv->atomic = req->value;
file_priv->universal_planes = req->value;
break;
+ case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS:
+ if (!file_priv->atomic || !drm_core_check_feature(dev,
DRIVER_ATOMIC))
+ return -EINVAL;
+ if (req->value > 1)
+ return -EINVAL;
+ file_priv->writeback_connectors = req->value;
+ break;
default:
return -EINVAL;
}
diff --git a/drivers/gpu/drm/drm_mode_config.c
b/drivers/gpu/drm/drm_mode_config.c
index e5c653357024d..21e353bd3948e 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -145,6 +145,11 @@ int drm_mode_getresources(struct drm_device *dev, void
*data,
count = 0;
connector_id = u64_to_user_ptr(card_res->connector_id_ptr);
drm_for_each_connector_iter(connector, &conn_iter) {
+ /* only expose writeback connectors if userspace understands
them */
+ if (!file_priv->writeback_connectors &&
+ (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK))
+ continue;
+
if (drm_lease_held(file_priv, connector->base.id)) {
if (count < card_res->count_connectors &&
put_user(connector->base.id, connector_id + count))
{
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 5176c3797680c..2a09b3c8965c6 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -181,6 +181,13 @@ struct drm_file {
/** @atomic: True if client understands atomic properties. */
unsigned atomic:1;
+ /**
+ * @writeback_connectors:
+ *
+ * True if client understands writeback connectors
+ */
+ unsigned writeback_connectors:1;
+
/**
* @is_master:
*
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 6fdff5945c8a0..59f27ea928b42 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -680,6 +680,15 @@ struct drm_get_cap {
*/
#define DRM_CLIENT_CAP_ATOMIC 3
+/**
+ * DRM_CLIENT_CAP_WRITEBACK_CONNECTORS
+ *
+ * If set to 1, the DRM core will expose special connectors to be used for
+ * writing back to memory the scene setup in the commit. Depends on client
+ * also supporting DRM_CLIENT_CAP_ATOMIC
+ */
+#define DRM_CLIENT_CAP_WRITEBACK_CONNECTORS 4
+
/** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
struct drm_set_client_cap {
__u64 capability;
--
2.17.0
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