diff mbox series

[v8,3/3] drm: writeback: Add client capability for exposing writeback connectors

Message ID 20180518151743.29937-4-Liviu.Dudau@arm.com
State Superseded
Headers show
Series None | expand

Commit Message

Liviu Dudau May 18, 2018, 3:17 p.m. UTC 
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 <seanpaul@chromium.org>
Cc: Brian Starkey <brian.starkey@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@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(+)

-- 
2.17.0

Comments

Liviu Dudau May 23, 2018, 12:27 p.m. UTC | #1 
On Wed, May 23, 2018 at 11:34:32AM +0200, Maarten Lankhorst wrote:
> Op 18-05-18 om 17:17 schreef Liviu Dudau:

> > 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 <seanpaul@chromium.org>

> > Cc: Brian Starkey <brian.starkey@arm.com>

> > Signed-off-by: Liviu Dudau <liviu.dudau@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;

> Wondering how you can set the atomic cap without DRIVER_ATOMIC. :)


Caps can only be set one at a time. I was trying to cater for the cases
where userspace can set the WRITEBACK_CONNECTORS client cap before or
after setting the atomic cap.

> 

> That part could be dropped I think. We should probably WARN when trying to create a writeback connector without the DRIVER_ATOMIC cap set.


I could still keep the check for file_priv->atomic being set when
accepting the DRM_CLIENT_CAP_WRITEBACK_CONNECTORS and would not need a
warn.

Best regards,
Liviu

> > +		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;

> 

> ~Maarten

> 


-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
    ¯\_(ツ)_/¯
Daniel Vetter May 24, 2018, 7:50 a.m. UTC | #2 
On Wed, May 23, 2018 at 01:27:17PM +0100, Liviu Dudau wrote:
> On Wed, May 23, 2018 at 11:34:32AM +0200, Maarten Lankhorst wrote:

> > Op 18-05-18 om 17:17 schreef Liviu Dudau:

> > > 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 <seanpaul@chromium.org>

> > > Cc: Brian Starkey <brian.starkey@arm.com>

> > > Signed-off-by: Liviu Dudau <liviu.dudau@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;

> > Wondering how you can set the atomic cap without DRIVER_ATOMIC. :)

> 

> Caps can only be set one at a time. I was trying to cater for the cases

> where userspace can set the WRITEBACK_CONNECTORS client cap before or

> after setting the atomic cap.


The way we usually solve this is that if there's a dependency in caps, we
set them all. E.g. atomic above also sets universal planes. I recommend we
do the same for writeback.

> > That part could be dropped I think. We should probably WARN when trying to create a writeback connector without the DRIVER_ATOMIC cap set.

> 

> I could still keep the check for file_priv->atomic being set when

> accepting the DRM_CLIENT_CAP_WRITEBACK_CONNECTORS and would not need a

> warn.


Or this.
-Daniel

> 

> Best regards,

> Liviu

> 

> > > +		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;

> > 

> > ~Maarten

> > 

> 

> -- 

> ====================

> | I would like to |

> | fix the world,  |

> | but they're not |

> | giving me the   |

>  \ source code!  /

>   ---------------

>     ¯\_(ツ)_/¯

> _______________________________________________

> dri-devel mailing list

> dri-devel@lists.freedesktop.org

> https://lists.freedesktop.org/mailman/listinfo/dri-devel


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
diff mbox series

Patch

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;