On Wed, Oct 26, 2016 at 01:00:21PM +0200, Daniel Vetter wrote:
>On Wed, Oct 26, 2016 at 09:55:00AM +0100, Brian Starkey wrote:
>> Writeback connectors represent writeback engines which can write the
>> CRTC output to a memory framebuffer. Add a writeback connector type and
>> related support functions.
>>
>> Drivers should initialize a writeback connector with
>> drm_writeback_connector_init() which takes care of setting up all the
>> writeback-specific details on top of the normal functionality of
>> drm_connector_init().
>>
>> Writeback connectors have a WRITEBACK_FB_ID property, used to set the
>> output framebuffer, PIXEL_FORMATS and PIXEL_FORMATS_SIZE used to expose
>> the supported writeback formats to userspace.
>>
>> The drm_atomic core takes care of enforcing fairly strict semantics on
>> the use of writeback connectors. In short, a writeback connector can
>> only be included in a commit if it has both a framebuffer and a CRTC.
>> Conversely, you may not attach a framebuffer if the connector is not
>> attached to a CRTC, or if the CRTC is disabled.
>>
>> When a framebuffer is attached to a writeback connector with the
>> WRITEBACK_FB_ID property, it is used only once (for the commit in which
>> it was included), and userspace can never read back the value of
>> WRITEBACK_FB_ID.
>>
>> Changes since v1:
>> - Added drm_writeback.c + documentation
>> - Added helper to initialize writeback connector in one go
>> - Added core checks
>> - Squashed into a single commit
>> - Dropped the client cap
>> - Writeback framebuffers are no longer persistent
>>
>> Signed-off-by: Brian Starkey <brian.starkey at arm.com>
>
>I think this is looking pretty good. Bunch of nitpicks below, but
>otherwise I think we just need the userspace for this, plus an ack from
>other people interested in this, and it's good to get merged.
>-Daniel
>
Thanks for having another look,
>> ---
>> Documentation/gpu/drm-kms.rst | 9 ++
>> drivers/gpu/drm/Makefile | 2 +-
>> drivers/gpu/drm/drm_atomic.c | 95 +++++++++++++++++++++
>> drivers/gpu/drm/drm_atomic_helper.c | 5 ++
>> drivers/gpu/drm/drm_connector.c | 4 +-
>> drivers/gpu/drm/drm_writeback.c | 157
>> +++++++++++++++++++++++++++++++++++
>> include/drm/drm_atomic.h | 3 +
>> include/drm/drm_connector.h | 12 +++
>> include/drm/drm_crtc.h | 20 +++++
>> include/drm/drm_writeback.h | 19 +++++
>> include/uapi/drm/drm_mode.h | 1 +
>> 11 files changed, 325 insertions(+), 2 deletions(-)
>> create mode 100644 drivers/gpu/drm/drm_writeback.c
>> create mode 100644 include/drm/drm_writeback.h
>>
>> diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
>> index 53b872c..c3d0370 100644
>> --- a/Documentation/gpu/drm-kms.rst
>> +++ b/Documentation/gpu/drm-kms.rst
>> @@ -149,6 +149,15 @@ Connector Functions Reference
>> .. kernel-doc:: drivers/gpu/drm/drm_connector.c
>> :export:
>>
>> +Writeback Connectors
>> +--------------------
>> +
>> +.. kernel-doc:: drivers/gpu/drm/drm_writeback.c
>> + :doc: overview
>> +
>> +.. kernel-doc:: drivers/gpu/drm/drm_writeback.c
>> + :export:
>> +
>> Encoder Abstraction
>> ===================
>>
>> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
>> index 25c7204..2dc4a48 100644
>> --- a/drivers/gpu/drm/Makefile
>> +++ b/drivers/gpu/drm/Makefile
>> @@ -15,7 +15,7 @@ drm-y := drm_auth.o drm_bufs.o drm_cache.o \
>> drm_modeset_lock.o drm_atomic.o drm_bridge.o \
>> drm_framebuffer.o drm_connector.o drm_blend.o \
>> drm_encoder.o drm_mode_object.o drm_property.o \
>> - drm_plane.o drm_color_mgmt.o
>> + drm_plane.o drm_color_mgmt.o drm_writeback.o
>>
>> drm-$(CONFIG_COMPAT) += drm_ioc32.o
>> drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
>> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>> index fe37987..f434f34 100644
>> --- a/drivers/gpu/drm/drm_atomic.c
>> +++ b/drivers/gpu/drm/drm_atomic.c
>> @@ -612,6 +612,44 @@ static int drm_atomic_crtc_check(struct drm_crtc *crtc,
>> }
>>
>> /**
>> + * drm_atomic_connector_check - check connector state
>> + * @connector: connector to check
>> + * @state: connector state to check
>> + *
>> + * Provides core sanity checks for connector state.
>> + *
>> + * RETURNS:
>> + * Zero on success, error code on failure
>> + */
>> +static int drm_atomic_connector_check(struct drm_connector *connector,
>> + struct drm_connector_state *state)
>> +{
>> + struct drm_crtc_state *crtc_state;
>> +
>> + if (connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK)
>> + return 0;
>> +
>> + if (!state->fb != !state->crtc) {
>> + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] framebuffer/CRTC
>> mismatch\n",
>> + connector->base.id, connector->name);
>> + return -EINVAL;
>> + }
>> +
>> + if (state->crtc)
>> + crtc_state = drm_atomic_get_existing_crtc_state(state->state,
>> + state->crtc);
>> +
>> + if (state->fb && !crtc_state->active) {
>> + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] has framebuffer, but
>> [CRTC:%d] is off\n",
>> + connector->base.id, connector->name,
>> + state->crtc->base.id);
>> + return -EINVAL;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> * drm_atomic_get_plane_state - get plane state
>> * @state: global atomic state object
>> * @plane: plane to get state object for
>> @@ -1004,12 +1042,19 @@ int drm_atomic_connector_set_property(struct
>> drm_connector *connector,
>> * now?) atomic writes to DPMS property:
>> */
>> return -EINVAL;
>> + } else if (property == config->writeback_fb_id_property) {
>> + struct drm_framebuffer *fb = drm_framebuffer_lookup(dev, val);
>> + drm_atomic_set_fb_for_connector(state, fb);
>> + if (fb)
>> + drm_framebuffer_unreference(fb);
>> } else if (connector->funcs->atomic_set_property) {
>> return connector->funcs->atomic_set_property(connector,
>> state, property, val);
>> } else {
>> return -EINVAL;
>> }
>> +
>> + return 0;
>> }
>> EXPORT_SYMBOL(drm_atomic_connector_set_property);
>>
>> @@ -1040,6 +1085,9 @@ drm_atomic_connector_get_property(struct drm_connector
>> *connector,
>> *val = (state->crtc) ? state->crtc->base.id : 0;
>> } else if (property == config->dpms_property) {
>> *val = connector->dpms;
>> + } else if (property == config->writeback_fb_id_property) {
>> + /* Writeback framebuffer is one-shot, write and forget */
>> + *val = 0;
>> } else if (connector->funcs->atomic_get_property) {
>> return connector->funcs->atomic_get_property(connector,
>> state, property, val);
>> @@ -1223,6 +1271,42 @@ drm_atomic_set_crtc_for_connector(struct
>> drm_connector_state *conn_state,
>> EXPORT_SYMBOL(drm_atomic_set_crtc_for_connector);
>>
>> /**
>> + * drm_atomic_set_fb_for_connector - set framebuffer for (writeback)
>> connector
>
>Hm, I'd call this set_writeback_fb_for_connector, for even more
>obviousness.
>
Sure.
>> + * @conn_state: atomic state object for the connector
>> + * @fb: fb to use for the connector
>> + *
>> + * This is used to set the framebuffer for a writeback connector, which
>> outputs
>> + * to a buffer instead of an actual physical connector.
>> + * Changing the assigned framebuffer requires us to grab a reference to the
>> new
>> + * fb and drop the reference to the old fb, if there is one. This function
>> + * takes care of all these details besides updating the pointer in the
>> + * state object itself.
>> + *
>> + * Note: The only way conn_state can already have an fb set is if the commit
>> + * sets the property more than once.
>> + *
>> + * See also DOC: overview in drm_writeback.c
>> + */
>> +void
>> +drm_atomic_set_fb_for_connector(struct drm_connector_state *conn_state,
>> + struct drm_framebuffer *fb)
>> +{
>
>Should we have a WARN_ON(conn_state->connector->type != WRITEBACK here)?
>Just for safety.
>
Yeah OK, certainly won't do any harm.
>> + if (conn_state->fb)
>> + drm_framebuffer_unreference(conn_state->fb);
>> + if (fb)
>> + drm_framebuffer_reference(fb);
>> + conn_state->fb = fb;
>> +
>> + if (fb)
>> + DRM_DEBUG_ATOMIC("Set [FB:%d] for connector state %p\n",
>> + fb->base.id, conn_state);
>> + else
>> + DRM_DEBUG_ATOMIC("Set [NOFB] for connector state %p\n",
>> + conn_state);
>> +}
>> +EXPORT_SYMBOL(drm_atomic_set_fb_for_connector);
>> +
>> +/**
>> * drm_atomic_add_affected_connectors - add connectors for crtc
>> * @state: atomic state
>> * @crtc: DRM crtc
>> @@ -1376,6 +1460,8 @@ int drm_atomic_check_only(struct drm_atomic_state
>> *state)
>> struct drm_plane_state *plane_state;
>> struct drm_crtc *crtc;
>> struct drm_crtc_state *crtc_state;
>> + struct drm_connector *conn;
>> + struct drm_connector_state *conn_state;
>> int i, ret = 0;
>>
>> DRM_DEBUG_ATOMIC("checking %p\n", state);
>> @@ -1398,6 +1484,15 @@ int drm_atomic_check_only(struct drm_atomic_state
>> *state)
>> }
>> }
>>
>> + for_each_connector_in_state(state, conn, conn_state, i) {
>> + ret = drm_atomic_connector_check(conn, conn_state);
>> + if (ret) {
>> + DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] atomic core check
>> failed\n",
>> + conn->base.id, conn->name);
>> + return ret;
>> + }
>> + }
>> +
>> if (config->funcs->atomic_check)
>> ret = config->funcs->atomic_check(state->dev, state);
>>
>> diff --git a/drivers/gpu/drm/drm_atomic_helper.c
>> b/drivers/gpu/drm/drm_atomic_helper.c
>> index 2c44de3..bba8672 100644
>> --- a/drivers/gpu/drm/drm_atomic_helper.c
>> +++ b/drivers/gpu/drm/drm_atomic_helper.c
>> @@ -3233,6 +3233,9 @@ __drm_atomic_helper_connector_duplicate_state(struct
>> drm_connector *connector,
>> memcpy(state, connector->state, sizeof(*state));
>> if (state->crtc)
>> drm_connector_reference(connector);
>> +
>> + /* Don't copy over framebuffers, they are used only once */
>> + state->fb = NULL;
>> }
>> EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
>>
>> @@ -3360,6 +3363,8 @@ __drm_atomic_helper_connector_destroy_state(struct
>> drm_connector_state *state)
>> */
>> if (state->crtc)
>> drm_connector_unreference(state->connector);
>> + if (state->fb)
>> + drm_framebuffer_unreference(state->fb);
>> }
>> EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state);
>>
>> diff --git a/drivers/gpu/drm/drm_connector.c
>> b/drivers/gpu/drm/drm_connector.c
>> index 2db7fb5..e67084d 100644
>> --- a/drivers/gpu/drm/drm_connector.c
>> +++ b/drivers/gpu/drm/drm_connector.c
>> @@ -86,6 +86,7 @@ static struct drm_conn_prop_enum_list
>> drm_connector_enum_list[] = {
>> { DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" },
>> { DRM_MODE_CONNECTOR_DSI, "DSI" },
>> { DRM_MODE_CONNECTOR_DPI, "DPI" },
>> + { DRM_MODE_CONNECTOR_WRITEBACK, "Writeback" },
>> };
>>
>> void drm_connector_ida_init(void)
>> @@ -235,7 +236,8 @@ int drm_connector_init(struct drm_device *dev,
>> list_add_tail(&connector->head, &config->connector_list);
>> config->num_connector++;
>>
>> - if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL)
>> + if ((connector_type != DRM_MODE_CONNECTOR_VIRTUAL) &&
>> + (connector_type != DRM_MODE_CONNECTOR_WRITEBACK))
>> drm_object_attach_property(&connector->base,
>> config->edid_property,
>> 0);
>> diff --git a/drivers/gpu/drm/drm_writeback.c
>> b/drivers/gpu/drm/drm_writeback.c
>> new file mode 100644
>> index 0000000..5a6e0ad
>> --- /dev/null
>> +++ b/drivers/gpu/drm/drm_writeback.c
>> @@ -0,0 +1,157 @@
>> +/*
>> + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved.
>> + * Author: Brian Starkey <brian.starkey at arm.com>
>> + *
>> + * This program is free software and is provided to you under the terms of
>> the
>> + * GNU General Public License version 2 as published by the Free Software
>> + * Foundation, and any use by you of this program is subject to the terms
>> + * of such GNU licence.
>> + */
>> +
>> +#include <drm/drm_crtc.h>
>> +#include <drm/drm_property.h>
>> +#include <drm/drmP.h>
>> +
>> +/**
>> + * DOC: overview
>> + *
>> + * Writeback connectors are used to expose hardware which can write the
>> output
>> + * from a CRTC to a memory buffer. They are used and act similarly to other
>> + * types of connectors, with some important differences:
>> + * - Writeback connectors don't provide a way to output visually to the
>> user.
>> + * - Writeback connectors should always report as "disconnected" (so that
>> + * clients which don't understand them will ignore them).
>> + * - Writeback connectors don't have EDID.
>> + *
>> + * Writeback connectors may only be attached to a CRTC when they have a
>> + * framebuffer attached, and may only have a framebuffer attached when they
>> are
>> + * attached to a CRTC. The WRITEBACK_FB_ID property which sets the
>> framebuffer
>> + * applies only to a single commit (see below), which means that each and
>> every
>> + * commit which makes use of a writeback connector must set both its
>> CRTC_ID and
>> + * WRITEBACK_FB_ID. It also means that the connector's CRTC_ID must be
>> + * explicitly cleared in order to make a subsequent commit which doesn't use
>> + * writeback.
>
>Hm, this is a bit an ugly fallout from our safety checks, but I guess it's
>a reasonable requirement for userspace. Writeback is kinda special. Or
>should we make the ->crtc pointer one-shot too? Of course only for
>writeback pointers. I think that would make is simpler to use in libraries
>like igt.
>
I sort-of agree on the ugly fallout sentiment, it took me a bit by
surprise when some of my commits started failing :-). On the userspace
side it isn't really any additional effort once you understand the
requirements though (which you learn quickly by way of -EINVAL).
I'm actually leaning towards leaving it as-is for two reasons:
1) On hardware that actually *does* need a full-modeset for writeback
routing changes, a one-shot CRTC would cause problems (need a
full-modeset every frame).
2) If there's no explicit commit to disable, we have no way to
communicate to the driver that it should disable - no-one will
ever add the connector_state to the next commit.
Both of the above *could* be handled with some special casing, but my
gut feeling is it would be tricky and a bit of a mess.
The current implementation is reasonably clean, and does seem to have
removed a few corner cases which would be likely sources of driver
bugs.
>> + *
>> + * Writeback connectors have several additional properties, which userspace
>> + * can use to query and control them:
>> + *
>> + * "WRITEBACK_FB_ID":
>> + * Write-only object property storing a DRM_MODE_OBJECT_FB: it stores the
>> + * framebuffer to be written by the writeback connector. This property is
>> + * similar to the FB_ID property on planes, but will always read as zero
>> + * and is not preserved across commits.
>> + * Userspace must set this property to an output buffer every time it
>> + * wishes the buffer to get filled.
>> + *
>> + * "PIXEL_FORMATS":
>> + * Immutable blob property to store the supported pixel formats table. The
>> + * data is an array of u32 DRM_FORMAT_* fourcc values.
>> + * Userspace can use this blob to find out what pixel formats are supported
>> + * by the connector's writeback engine.
>> + *
>> + * "PIXEL_FORMATS_SIZE":
>> + * Immutable unsigned range property storing the number of entries in the
>> + * PIXEL_FORMATS array.
>
>Blob properties already have a size, you don't need to specify it.
>Gamma tables have a size since they start out with a default of NULL, so
>userspace has no idea what the size should be.
>
OK, that makes sense. I'll drop it.
>Docs are missing to clarify when the writeout is complete. Should we wait
>with merging this until out fences are supported, or should we add a bit
>of placeholder text here that the writeback will be completed 1 vblank
>after this atomic commit was committed? I'm leaning towards including the
>writeout out fences from the start.
>
Docs are missing because without fences I don't think it can be
defined ;-)
You think I should squash fences into this commit then? It's getting
somewhat large, but I'm not spotting any obvious places to split it
up anymore.
>> + */
>> +
>> +/**
>> + * create_writeback_properties - Create writeback connector-specific
>> properties
>> + * @dev: DRM device
>> + *
>> + * Create the properties specific to writeback connectors. These will be
>> + * attached to the connector and initialised by
>> drm_writeback_connector_init.
>> + *
>> + * Returns: true on success, or false if any property creation fails.
>> + */
>
>We don't do kernel-doc for non-EXPORT_SYMBOL functions, since the intended
>audience is driver authors. And I think this function here is clear enough
>that we don't need even a normal comment for it.
>
Right, I must have copied and blindly modified without thinking.
>> +static bool create_writeback_properties(struct drm_device *dev)
>> +{
>> + struct drm_property *prop;
>> +
>> + if (!dev->mode_config.writeback_fb_id_property) {
>> + prop = drm_property_create_object(dev, DRM_MODE_PROP_ATOMIC,
>> + "WRITEBACK_FB_ID",
>> + DRM_MODE_OBJECT_FB);
>> + if (!prop)
>> + return false;
>> + dev->mode_config.writeback_fb_id_property = prop;
>> + }
>> +
>> + if (!dev->mode_config.pixel_formats_property) {
>> + prop = drm_property_create(dev, DRM_MODE_PROP_BLOB |
>> DRM_MODE_PROP_IMMUTABLE,
>> + "PIXEL_FORMATS", 0);
>> + if (!prop)
>> + return false;
>> + dev->mode_config.pixel_formats_property = prop;
>> + }
>> +
>> + if (!dev->mode_config.pixel_formats_size_property) {
>> + prop = drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE,
>> + "PIXEL_FORMATS_SIZE", 0,
>> + UINT_MAX);
>> + if (!prop)
>> + return false;
>> + dev->mode_config.pixel_formats_size_property = prop;
>> + }
>> +
>> + return true;
>> +}
>> +
>> +/**
>> + * drm_writeback_connector_init - Initialize a writeback connector and its
>> properties
>> + * @dev: DRM device
>> + * @connector: Connector to initialize
>> + * @funcs: Connector funcs vtable
>> + * @formats: Array of supported pixel formats for the writeback engine
>> + * @n_formats: Length of the formats array
>> + *
>> + * This function creates the writeback-connector-specific properties if they
>> + * have not been already created, initializes the connector as
>> + * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
>> + * values.
>> + *
>> + * Drivers should always use this function instead of drm_connector_init()
>> to
>> + * set up writeback connectors.
>> + *
>> + * Returns: 0 on success, or a negative error code
>> + */
>> +int drm_writeback_connector_init(struct drm_device *dev,
>> + struct drm_connector *connector,
>> + const struct drm_connector_funcs *funcs,
>> + u32 *formats, int n_formats)
>> +{
>> + int ret;
>> + struct drm_property_blob *blob;
>> + struct drm_mode_config *config = &dev->mode_config;
>> +
>> + if (!create_writeback_properties(dev))
>> + return -EINVAL;
>> +
>> + blob = drm_property_create_blob(dev, n_formats * sizeof(*formats),
>> + formats);
>> + if (IS_ERR(blob))
>> + return PTR_ERR(blob);
>> +
>> + ret = drm_connector_init(dev, connector, funcs,
>> + DRM_MODE_CONNECTOR_WRITEBACK);
>> + if (ret)
>> + goto fail;
>> +
>> + drm_object_attach_property(&connector->base,
>> + config->writeback_fb_id_property, 0);
>> +
>> + drm_object_attach_property(&connector->base,
>> + config->pixel_formats_property,
>> + blob->base.id);
>> + connector->pixel_formats_blob_ptr = blob;
>> +
>> + drm_object_attach_property(&connector->base,
>> + config->pixel_formats_size_property,
>> + n_formats);
>> +
>> + return 0;
>> +
>> +fail:
>> + drm_property_unreference_blob(blob);
>> + return ret;
>> +}
>> +EXPORT_SYMBOL(drm_writeback_connector_init);
>> diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
>> index 9701f2d..d9aff06 100644
>> --- a/include/drm/drm_atomic.h
>> +++ b/include/drm/drm_atomic.h
>> @@ -319,6 +319,9 @@ void drm_atomic_set_fb_for_plane(struct drm_plane_state
>> *plane_state,
>> int __must_check
>> drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
>> struct drm_crtc *crtc);
>> +void
>> +drm_atomic_set_fb_for_connector(struct drm_connector_state *conn_state,
>> + struct drm_framebuffer *fb);
>> int __must_check
>> drm_atomic_add_affected_connectors(struct drm_atomic_state *state,
>> struct drm_crtc *crtc);
>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>> index ac9d7d8..a5e3778 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -198,6 +198,7 @@ int drm_display_info_set_bus_formats(struct
>> drm_display_info *info,
>> * @connector: backpointer to the connector
>> * @best_encoder: can be used by helpers and drivers to select the encoder
>> * @state: backpointer to global drm_atomic_state
>> + * @fb: Writeback framebuffer, for DRM_MODE_CONNECTOR_WRITEBACK
>> */
>> struct drm_connector_state {
>> struct drm_connector *connector;
>> @@ -213,6 +214,8 @@ struct drm_connector_state {
>> struct drm_encoder *best_encoder;
>>
>> struct drm_atomic_state *state;
>> +
>> + struct drm_framebuffer *fb; /* do not write directly, use
>> drm_atomic_set_fb_for_connector() */
>> };
>>
>> /**
>> @@ -612,6 +615,15 @@ struct drm_connector {
>> */
>> struct drm_property_blob *tile_blob_ptr;
>>
>> + /**
>> + * @pixel_formats_blob_ptr:
>> + *
>> + * DRM blob property data for the pixel formats list on writeback
>> + * connectors
>> + * See also DOC: overview in drm_writeback.c
>
>Ah, here's the link you wanted. Imo just use
>drm_writeback_connector_init() instead, that's a link close enough to your
>target.
>
OK.
>> + */
>> + struct drm_property_blob *pixel_formats_blob_ptr;
>
>I'g go with a writeout prefix.
OK.
>> +
>> /* should we poll this connector for connects and disconnects */
>> /* hot plug detectable */
>> #define DRM_CONNECTOR_POLL_HPD (1 << 0)
>> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
>> index fe20d8f..378baee2 100644
>> --- a/include/drm/drm_crtc.h
>> +++ b/include/drm/drm_crtc.h
>> @@ -1345,6 +1345,26 @@ struct drm_mode_config {
>> */
>> struct drm_property *suggested_y_property;
>>
>> + /**
>> + * @writeback_fb_id_property: Property for writeback connectors, storing
>> + * the ID of the output framebuffer.
>> + * See also DOC: overview in drm_writeback.c
>
>Same here and all of the below.
>
>> + */
>> + struct drm_property *writeback_fb_id_property;
>> + /**
>> + * @pixel_formats_property: Property for writeback connectors, storing
>> + * an array of the supported pixel formats for the writeback engine
>> + * (read-only).
>> + * See also DOC: overview in drm_writeback.c
>> + */
>> + struct drm_property *pixel_formats_property;
>> + /**
>> + * @pixel_formats_size_property: Property for writeback connectors,
>> + * stating the size of the pixel formats array (read-only).
>> + * See also DOC: overview in drm_writeback.c
>> + */
>> + struct drm_property *pixel_formats_size_property;
>> +
>> /* dumb ioctl parameters */
>> uint32_t preferred_depth, prefer_shadow;
>>
>> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
>> new file mode 100644
>> index 0000000..afdc2742
>> --- /dev/null
>> +++ b/include/drm/drm_writeback.h
>> @@ -0,0 +1,19 @@
>> +/*
>> + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved.
>> + * Author: Brian Starkey <brian.starkey at arm.com>
>> + *
>> + * This program is free software and is provided to you under the terms of
>> the
>> + * GNU General Public License version 2 as published by the Free Software
>> + * Foundation, and any use by you of this program is subject to the terms
>> + * of such GNU licence.
>> + */
>> +
>> +#ifndef __DRM_WRITEBACK_H__
>> +#define __DRM_WRITEBACK_H__
>> +
>> +int drm_writeback_connector_init(struct drm_device *dev,
>> + struct drm_connector *connector,
>> + const struct drm_connector_funcs *funcs,
>> + u32 *formats, int n_formats);
>> +
>> +#endif
>> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
>> index df0e350..e9cb4fe 100644
>> --- a/include/uapi/drm/drm_mode.h
>> +++ b/include/uapi/drm/drm_mode.h
>> @@ -247,6 +247,7 @@ struct drm_mode_get_encoder {
>> #define DRM_MODE_CONNECTOR_VIRTUAL 15
>> #define DRM_MODE_CONNECTOR_DSI 16
>> #define DRM_MODE_CONNECTOR_DPI 17
>> +#define DRM_MODE_CONNECTOR_WRITEBACK 18
>>
>> struct drm_mode_get_connector {
>>
>> --
>> 1.7.9.5
>>
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
>--
>Daniel Vetter
>Software Engineer, Intel Corporation
>http://blog.ffwll.ch
>
