Hi,
This is v10 of the writeback connector series. Compared to v9 I've
reverted to the v6 way of cleaning up the writeback job in the cleanup_work()
function, where we also drop the reference to the job's framebuffer. I was
trying to come up with a reference counted implementation for the job, but
Sean Paul pointed out to Brian that it seems to be safe to free work_struct
structures in the workqueue callback, so we are going back to the original
implementation.
While doing that, I've also updated the patcheset to use the latest
drm_framebuffer_{put,get,assign} functions for managing the framebuffer
reference that the wriback job holds.
I will ask Gustavo to pull this series into drm-misc if there are no further
comments.
Best regards,
Liviu
Brian Starkey (2):
drm: Add writeback connector type
drm: writeback: Add out-fences for writeback connectors
Liviu Dudau (1):
drm: writeback: Add client capability for exposing writeback
connectors
Documentation/gpu/drm-kms.rst | 9 +
drivers/gpu/drm/Makefile | 2 +-
drivers/gpu/drm/drm_atomic.c | 223 ++++++++++++++-
drivers/gpu/drm/drm_atomic_helper.c | 25 ++
drivers/gpu/drm/drm_connector.c | 4 +-
drivers/gpu/drm/drm_ioctl.c | 7 +
drivers/gpu/drm/drm_mode_config.c | 5 +
drivers/gpu/drm/drm_writeback.c | 350 +++++++++++++++++++++++
include/drm/drm_atomic.h | 11 +
include/drm/drm_connector.h | 13 +
include/drm/drm_file.h | 7 +
include/drm/drm_mode_config.h | 23 ++
include/drm/drm_modeset_helper_vtables.h | 11 +
include/drm/drm_writeback.h | 130 +++++++++
include/uapi/drm/drm.h | 9 +
include/uapi/drm/drm_mode.h | 1 +
16 files changed, 819 insertions(+), 11 deletions(-)
create mode 100644 drivers/gpu/drm/drm_writeback.c
create mode 100644 include/drm/drm_writeback.h
--
2.17.1
From: Brian Starkey <[email protected]>
Add the WRITEBACK_OUT_FENCE_PTR property to writeback connectors, to
enable userspace to get a fence which will signal once the writeback is
complete. It is not allowed to request an out-fence without a
framebuffer attached to the connector.
A timeline is added to drm_writeback_connector for use by the writeback
out-fences.
In the case of a commit failure or DRM_MODE_ATOMIC_TEST_ONLY, the fence
is set to -1.
Changes from v2:
- Rebase onto Gustavo Padovan's v9 explicit sync series
- Change out_fence_ptr type to s32 __user *
- Set *out_fence_ptr to -1 in drm_atomic_connector_set_property
- Store fence in drm_writeback_job
Gustavo Padovan:
- Move out_fence_ptr out of connector_state
- Signal fence from drm_writeback_signal_completion instead of
in driver directly
Changes from v3:
- Rebase onto commit 7e9081c5aac7 ("drm/fence: fix memory overwrite
when setting out_fence fd") (change out_fence_ptr to s32 __user *,
for real this time.)
- Update documentation around WRITEBACK_OUT_FENCE_PTR
Signed-off-by: Brian Starkey <[email protected]>
[rebased and fixed conflicts]
Signed-off-by: Mihail Atanassov <[email protected]>
Signed-off-by: Liviu Dudau <[email protected]>
---
drivers/gpu/drm/drm_atomic.c | 99 ++++++++++++++++++++++++++---
drivers/gpu/drm/drm_writeback.c | 109 +++++++++++++++++++++++++++++++-
include/drm/drm_atomic.h | 8 +++
include/drm/drm_connector.h | 8 +--
include/drm/drm_mode_config.h | 8 +++
include/drm/drm_writeback.h | 41 +++++++++++-
6 files changed, 257 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index f2400c77fe3f3..db3cb47da31b6 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -326,6 +326,35 @@ static s32 __user *get_out_fence_for_crtc(struct drm_atomic_state *state,
return fence_ptr;
}
+static int set_out_fence_for_connector(struct drm_atomic_state *state,
+ struct drm_connector *connector,
+ s32 __user *fence_ptr)
+{
+ unsigned int index = drm_connector_index(connector);
+
+ if (!fence_ptr)
+ return 0;
+
+ if (put_user(-1, fence_ptr))
+ return -EFAULT;
+
+ state->connectors[index].out_fence_ptr = fence_ptr;
+
+ return 0;
+}
+
+static s32 __user *get_out_fence_for_connector(struct drm_atomic_state *state,
+ struct drm_connector *connector)
+{
+ unsigned int index = drm_connector_index(connector);
+ s32 __user *fence_ptr;
+
+ fence_ptr = state->connectors[index].out_fence_ptr;
+ state->connectors[index].out_fence_ptr = NULL;
+
+ return fence_ptr;
+}
+
/**
* drm_atomic_set_mode_for_crtc - set mode for CRTC
* @state: the CRTC whose incoming state to update
@@ -713,6 +742,12 @@ static int drm_atomic_connector_check(struct drm_connector *connector,
return -EINVAL;
}
+ if (writeback_job->out_fence && !writeback_job->fb) {
+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] requesting out-fence without framebuffer\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+
return 0;
}
@@ -1332,6 +1367,11 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector,
if (fb)
drm_framebuffer_put(fb);
return ret;
+ } else if (property == config->writeback_out_fence_ptr_property) {
+ s32 __user *fence_ptr = u64_to_user_ptr(val);
+
+ return set_out_fence_for_connector(state->state, connector,
+ fence_ptr);
} else if (connector->funcs->atomic_set_property) {
return connector->funcs->atomic_set_property(connector,
state, property, val);
@@ -1416,6 +1456,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
} else if (property == config->writeback_fb_id_property) {
/* Writeback framebuffer is one-shot, write and forget */
*val = 0;
+ } else if (property == config->writeback_out_fence_ptr_property) {
+ *val = 0;
} else if (connector->funcs->atomic_get_property) {
return connector->funcs->atomic_get_property(connector,
state, property, val);
@@ -2285,7 +2327,7 @@ static int setup_out_fence(struct drm_out_fence_state *fence_state,
return 0;
}
-static int prepare_crtc_signaling(struct drm_device *dev,
+static int prepare_signaling(struct drm_device *dev,
struct drm_atomic_state *state,
struct drm_mode_atomic *arg,
struct drm_file *file_priv,
@@ -2294,6 +2336,8 @@ static int prepare_crtc_signaling(struct drm_device *dev,
{
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
+ struct drm_connector *conn;
+ struct drm_connector_state *conn_state;
int i, c = 0, ret;
if (arg->flags & DRM_MODE_ATOMIC_TEST_ONLY)
@@ -2359,6 +2403,43 @@ static int prepare_crtc_signaling(struct drm_device *dev,
c++;
}
+ for_each_new_connector_in_state(state, conn, conn_state, i) {
+ struct drm_writeback_job *job;
+ struct drm_out_fence_state *f;
+ struct dma_fence *fence;
+ s32 __user *fence_ptr;
+
+ fence_ptr = get_out_fence_for_connector(state, conn);
+ if (!fence_ptr)
+ continue;
+
+ job = drm_atomic_get_writeback_job(conn_state);
+ if (!job)
+ return -ENOMEM;
+
+ f = krealloc(*fence_state, sizeof(**fence_state) *
+ (*num_fences + 1), GFP_KERNEL);
+ if (!f)
+ return -ENOMEM;
+
+ memset(&f[*num_fences], 0, sizeof(*f));
+
+ f[*num_fences].out_fence_ptr = fence_ptr;
+ *fence_state = f;
+
+ fence = drm_writeback_get_out_fence((struct drm_writeback_connector *)conn);
+ if (!fence)
+ return -ENOMEM;
+
+ ret = setup_out_fence(&f[(*num_fences)++], fence);
+ if (ret) {
+ dma_fence_put(fence);
+ return ret;
+ }
+
+ job->out_fence = fence;
+ }
+
/*
* Having this flag means user mode pends on event which will never
* reach due to lack of at least one CRTC for signaling
@@ -2369,11 +2450,11 @@ static int prepare_crtc_signaling(struct drm_device *dev,
return 0;
}
-static void complete_crtc_signaling(struct drm_device *dev,
- struct drm_atomic_state *state,
- struct drm_out_fence_state *fence_state,
- unsigned int num_fences,
- bool install_fds)
+static void complete_signaling(struct drm_device *dev,
+ struct drm_atomic_state *state,
+ struct drm_out_fence_state *fence_state,
+ unsigned int num_fences,
+ bool install_fds)
{
struct drm_crtc *crtc;
struct drm_crtc_state *crtc_state;
@@ -2552,8 +2633,8 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
drm_mode_object_put(obj);
}
- ret = prepare_crtc_signaling(dev, state, arg, file_priv, &fence_state,
- &num_fences);
+ ret = prepare_signaling(dev, state, arg, file_priv, &fence_state,
+ &num_fences);
if (ret)
goto out;
@@ -2571,7 +2652,7 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
out:
drm_atomic_clean_old_fb(dev, plane_mask, ret);
- complete_crtc_signaling(dev, state, fence_state, num_fences, !ret);
+ complete_signaling(dev, state, fence_state, num_fences, !ret);
if (ret == -EDEADLK) {
drm_atomic_state_clear(state);
diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
index e5b8a4b79724b..827395071f0b5 100644
--- a/drivers/gpu/drm/drm_writeback.c
+++ b/drivers/gpu/drm/drm_writeback.c
@@ -14,6 +14,7 @@
#include <drm/drm_property.h>
#include <drm/drm_writeback.h>
#include <drm/drmP.h>
+#include <linux/dma-fence.h>
/**
* DOC: overview
@@ -31,6 +32,16 @@
* framebuffer applies only to a single commit (see below). A framebuffer may
* not be attached while the CRTC is off.
*
+ * Unlike with planes, when a writeback framebuffer is removed by userspace DRM
+ * makes no attempt to remove it from active use by the connector. This is
+ * because no method is provided to abort a writeback operation, and in any
+ * case making a new commit whilst a writeback is ongoing is undefined (see
+ * WRITEBACK_OUT_FENCE_PTR below). As soon as the current writeback is finished,
+ * the framebuffer will automatically no longer be in active use. As it will
+ * also have already been removed from the framebuffer list, there will be no
+ * way for any userspace application to retrieve a reference to it in the
+ * intervening period.
+ *
* Writeback connectors have some additional properties, which userspace
* can use to query and control them:
*
@@ -47,8 +58,54 @@
* 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.
+ *
+ * "WRITEBACK_OUT_FENCE_PTR":
+ * Userspace can use this property to provide a pointer for the kernel to
+ * fill with a sync_file file descriptor, which will signal once the
+ * writeback is finished. The value should be the address of a 32-bit
+ * signed integer, cast to a u64.
+ * Userspace should wait for this fence to signal before making another
+ * commit affecting any of the same CRTCs, Planes or Connectors.
+ * **Failure to do so will result in undefined behaviour.**
+ * For this reason it is strongly recommended that all userspace
+ * applications making use of writeback connectors *always* retrieve an
+ * out-fence for the commit and use it appropriately.
+ * From userspace, this property will always read as zero.
*/
+#define fence_to_wb_connector(x) container_of(x->lock, \
+ struct drm_writeback_connector, \
+ fence_lock)
+
+static const char *drm_writeback_fence_get_driver_name(struct dma_fence *fence)
+{
+ struct drm_writeback_connector *wb_connector =
+ fence_to_wb_connector(fence);
+
+ return wb_connector->base.dev->driver->name;
+}
+
+static const char *
+drm_writeback_fence_get_timeline_name(struct dma_fence *fence)
+{
+ struct drm_writeback_connector *wb_connector =
+ fence_to_wb_connector(fence);
+
+ return wb_connector->timeline_name;
+}
+
+static bool drm_writeback_fence_enable_signaling(struct dma_fence *fence)
+{
+ return true;
+}
+
+static const struct dma_fence_ops drm_writeback_fence_ops = {
+ .get_driver_name = drm_writeback_fence_get_driver_name,
+ .get_timeline_name = drm_writeback_fence_get_timeline_name,
+ .enable_signaling = drm_writeback_fence_enable_signaling,
+ .wait = dma_fence_default_wait,
+};
+
static int create_writeback_properties(struct drm_device *dev)
{
struct drm_property *prop;
@@ -72,6 +129,15 @@ static int create_writeback_properties(struct drm_device *dev)
dev->mode_config.writeback_pixel_formats_property = prop;
}
+ if (!dev->mode_config.writeback_out_fence_ptr_property) {
+ prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC,
+ "WRITEBACK_OUT_FENCE_PTR", 0,
+ U64_MAX);
+ if (!prop)
+ return -ENOMEM;
+ dev->mode_config.writeback_out_fence_ptr_property = prop;
+ }
+
return 0;
}
@@ -141,6 +207,15 @@ int drm_writeback_connector_init(struct drm_device *dev,
INIT_LIST_HEAD(&wb_connector->job_queue);
spin_lock_init(&wb_connector->job_lock);
+ wb_connector->fence_context = dma_fence_context_alloc(1);
+ spin_lock_init(&wb_connector->fence_lock);
+ snprintf(wb_connector->timeline_name,
+ sizeof(wb_connector->timeline_name),
+ "CONNECTOR:%d-%s", connector->base.id, connector->name);
+
+ drm_object_attach_property(&connector->base,
+ config->writeback_out_fence_ptr_property, 0);
+
drm_object_attach_property(&connector->base,
config->writeback_fb_id_property, 0);
@@ -210,6 +285,7 @@ static void cleanup_work(struct work_struct *work)
/**
* drm_writeback_signal_completion - Signal the completion of a writeback job
* @wb_connector: The writeback connector whose job is complete
+ * @status: Status code to set in the writeback out_fence (0 for success)
*
* Drivers should call this to signal the completion of a previously queued
* writeback job. It should be called as soon as possible after the hardware
@@ -223,7 +299,8 @@ static void cleanup_work(struct work_struct *work)
* See also: drm_writeback_queue_job()
*/
void
-drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector)
+drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector,
+ int status)
{
unsigned long flags;
struct drm_writeback_job *job;
@@ -232,8 +309,15 @@ drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector)
job = list_first_entry_or_null(&wb_connector->job_queue,
struct drm_writeback_job,
list_entry);
- if (job)
+ if (job) {
list_del(&job->list_entry);
+ if (job->out_fence) {
+ if (status)
+ dma_fence_set_error(job->out_fence, status);
+ dma_fence_signal(job->out_fence);
+ dma_fence_put(job->out_fence);
+ }
+ }
spin_unlock_irqrestore(&wb_connector->job_lock, flags);
if (WARN_ON(!job))
@@ -243,3 +327,24 @@ drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector)
queue_work(system_long_wq, &job->cleanup_work);
}
EXPORT_SYMBOL(drm_writeback_signal_completion);
+
+struct dma_fence *
+drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector)
+{
+ struct dma_fence *fence;
+
+ if (WARN_ON(wb_connector->base.connector_type !=
+ DRM_MODE_CONNECTOR_WRITEBACK))
+ return NULL;
+
+ fence = kzalloc(sizeof(*fence), GFP_KERNEL);
+ if (!fence)
+ return NULL;
+
+ dma_fence_init(fence, &drm_writeback_fence_ops,
+ &wb_connector->fence_lock, wb_connector->fence_context,
+ ++wb_connector->fence_seqno);
+
+ return fence;
+}
+EXPORT_SYMBOL(drm_writeback_get_out_fence);
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index a5e904105db3a..7c77a1916182a 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -160,6 +160,14 @@ struct __drm_crtcs_state {
struct __drm_connnectors_state {
struct drm_connector *ptr;
struct drm_connector_state *state, *old_state, *new_state;
+ /**
+ * @out_fence_ptr:
+ *
+ * User-provided pointer which the kernel uses to return a sync_file
+ * file descriptor. Used by writeback connectors to signal completion of
+ * the writeback.
+ */
+ s32 __user *out_fence_ptr;
};
struct drm_private_obj;
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 60c0ffb947d5e..b0d2ed13d625b 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -433,10 +433,10 @@ struct drm_connector_state {
/**
* @writeback_job: Writeback job for writeback connectors
*
- * Holds the framebuffer for a writeback connector. As the writeback
- * completion may be asynchronous to the normal commit cycle, the
- * writeback job lifetime is managed separately from the normal atomic
- * state by this object.
+ * Holds the framebuffer and out-fence for a writeback connector. As
+ * the writeback completion may be asynchronous to the normal commit
+ * cycle, the writeback job lifetime is managed separately from the
+ * normal atomic state by this object.
*
* See also: drm_writeback_queue_job() and
* drm_writeback_signal_completion()
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 9ca32bf7bf183..d38ff4aab67b7 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -793,6 +793,14 @@ struct drm_mode_config {
* See also: drm_writeback_connector_init()
*/
struct drm_property *writeback_pixel_formats_property;
+ /**
+ * @writeback_out_fence_ptr_property: Property for writeback connectors,
+ * fd pointer representing the outgoing fences for a writeback
+ * connector. Userspace should provide a pointer to a value of type s32,
+ * and then cast that pointer to u64.
+ * See also: drm_writeback_connector_init()
+ */
+ struct drm_property *writeback_out_fence_ptr_property;
/* dumb ioctl parameters */
uint32_t preferred_depth, prefer_shadow;
diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
index 17cd1feecd7e5..a10fe556dfd45 100644
--- a/include/drm/drm_writeback.h
+++ b/include/drm/drm_writeback.h
@@ -50,6 +50,32 @@ struct drm_writeback_connector {
* drm_writeback_signal_completion()
*/
struct list_head job_queue;
+
+ /**
+ * @fence_context:
+ *
+ * timeline context used for fence operations.
+ */
+ unsigned int fence_context;
+ /**
+ * @fence_lock:
+ *
+ * spinlock to protect the fences in the fence_context.
+ */
+ spinlock_t fence_lock;
+ /**
+ * @fence_seqno:
+ *
+ * Seqno variable used as monotonic counter for the fences
+ * created on the connector's timeline.
+ */
+ unsigned long fence_seqno;
+ /**
+ * @timeline_name:
+ *
+ * The name of the connector's fence timeline.
+ */
+ char timeline_name[32];
};
struct drm_writeback_job {
@@ -75,6 +101,13 @@ struct drm_writeback_job {
* directly, use drm_atomic_set_writeback_fb_for_connector()
*/
struct drm_framebuffer *fb;
+
+ /**
+ * @out_fence:
+ *
+ * Fence which will signal once the writeback has completed
+ */
+ struct dma_fence *out_fence;
};
int drm_writeback_connector_init(struct drm_device *dev,
@@ -87,5 +120,11 @@ void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,
struct drm_writeback_job *job);
void drm_writeback_cleanup_job(struct drm_writeback_job *job);
-void drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector);
+
+void
+drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector,
+ int status);
+
+struct dma_fence *
+drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector);
#endif
--
2.17.1
From: Brian Starkey <[email protected]>
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, and a WRITEBACK_PIXEL_FORMATS blob used to expose the
supported writeback formats to userspace.
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. WRITEBACK_FB_ID can only be set if the connector is
attached to a CRTC.
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
Changes since v2:
Daniel Vetter:
- Subclass drm_connector to drm_writeback_connector
- Relax check to allow CRTC to be set without an FB
- Add some writeback_ prefixes
- Drop PIXEL_FORMATS_SIZE property, as it was unnecessary
Gustavo Padovan:
- Add drm_writeback_job to handle writeback signalling centrally
Changes since v3:
- Rebased
- Rename PIXEL_FORMATS -> WRITEBACK_PIXEL_FORMATS
Chances since v4:
- Embed a drm_encoder inside the drm_writeback_connector to
reduce the amount of boilerplate code required from the drivers
that are using it.
Changes since v5:
- Added Rob Clark's atomic_commit() vfunc to connector helper
funcs, so that writeback jobs are committed from atomic helpers
- Updated create_writeback_properties() signature to return an
error code rather than a boolean false for failure.
- Free writeback job with the connector state rather than when
doing the cleanup_work()
Changes since v7:
- fix extraneous use of out_fence that is only introduced in a
subsequent patch.
Changes since v8:
- whitespace changes pull from subsequent patch
Changes since v9:
- Revert the v6 changes that free the writeback job in the connector
state cleanup and return to doing it in the cleanup_work() function
Signed-off-by: Brian Starkey <[email protected]>
[rebased and fixed conflicts]
Signed-off-by: Mihail Atanassov <[email protected]>
[rebased and added atomic_commit() vfunc for writeback jobs]
Signed-off-by: Rob Clark <[email protected]>
Signed-off-by: Liviu Dudau <[email protected]>
---
Documentation/gpu/drm-kms.rst | 9 +
drivers/gpu/drm/Makefile | 2 +-
drivers/gpu/drm/drm_atomic.c | 124 ++++++++++++
drivers/gpu/drm/drm_atomic_helper.c | 25 +++
drivers/gpu/drm/drm_connector.c | 4 +-
drivers/gpu/drm/drm_writeback.c | 245 +++++++++++++++++++++++
include/drm/drm_atomic.h | 3 +
include/drm/drm_connector.h | 13 ++
include/drm/drm_mode_config.h | 15 ++
include/drm/drm_modeset_helper_vtables.h | 11 +
include/drm/drm_writeback.h | 91 +++++++++
include/uapi/drm/drm_mode.h | 1 +
12 files changed, 541 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 1dffd1ac4cd44..809d403087f95 100644
--- a/Documentation/gpu/drm-kms.rst
+++ b/Documentation/gpu/drm-kms.rst
@@ -373,6 +373,15 @@ 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 ef9f3dab287fd..69c13517ea3a6 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -18,7 +18,7 @@ drm-y := drm_auth.o drm_bufs.o drm_cache.o \
drm_encoder.o drm_mode_object.o drm_property.o \
drm_plane.o drm_color_mgmt.o drm_print.o \
drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
- drm_syncobj.o drm_lease.o
+ drm_syncobj.o drm_lease.o drm_writeback.o
drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
drm-$(CONFIG_DRM_VM) += drm_vm.o
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 895741e9cd7db..f2400c77fe3f3 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -30,6 +30,7 @@
#include <drm/drm_atomic.h>
#include <drm/drm_mode.h>
#include <drm/drm_print.h>
+#include <drm/drm_writeback.h>
#include <linux/sync_file.h>
#include "drm_crtc_internal.h"
@@ -676,6 +677,45 @@ static void drm_atomic_crtc_print_state(struct drm_printer *p,
crtc->funcs->atomic_print_state(p, state);
}
+/**
+ * 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;
+ struct drm_writeback_job *writeback_job = state->writeback_job;
+
+ if ((connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK) || !writeback_job)
+ return 0;
+
+ if (writeback_job->fb && !state->crtc) {
+ DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] framebuffer without CRTC\n",
+ connector->base.id, connector->name);
+ return -EINVAL;
+ }
+
+ if (state->crtc)
+ crtc_state = drm_atomic_get_existing_crtc_state(state->state,
+ state->crtc);
+
+ if (writeback_job->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
@@ -1286,6 +1326,12 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector,
return -EINVAL;
}
state->content_protection = val;
+ } else if (property == config->writeback_fb_id_property) {
+ struct drm_framebuffer *fb = drm_framebuffer_lookup(dev, NULL, val);
+ int ret = drm_atomic_set_writeback_fb_for_connector(state, fb);
+ if (fb)
+ drm_framebuffer_put(fb);
+ return ret;
} else if (connector->funcs->atomic_set_property) {
return connector->funcs->atomic_set_property(connector,
state, property, val);
@@ -1367,6 +1413,9 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
*val = state->scaling_mode;
} else if (property == connector->content_protection_property) {
*val = state->content_protection;
+ } 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);
@@ -1584,6 +1633,70 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
}
EXPORT_SYMBOL(drm_atomic_set_crtc_for_connector);
+/*
+ * drm_atomic_get_writeback_job - return or allocate a writeback job
+ * @conn_state: Connector state to get the job for
+ *
+ * Writeback jobs have a different lifetime to the atomic state they are
+ * associated with. This convenience function takes care of allocating a job
+ * if there isn't yet one associated with the connector state, otherwise
+ * it just returns the existing job.
+ *
+ * Returns: The writeback job for the given connector state
+ */
+static struct drm_writeback_job *
+drm_atomic_get_writeback_job(struct drm_connector_state *conn_state)
+{
+ WARN_ON(conn_state->connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK);
+
+ if (!conn_state->writeback_job)
+ conn_state->writeback_job =
+ kzalloc(sizeof(*conn_state->writeback_job), GFP_KERNEL);
+
+ return conn_state->writeback_job;
+}
+
+/**
+ * drm_atomic_set_writeback_fb_for_connector - set writeback framebuffer
+ * @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: drm_writeback_connector_init()
+ *
+ * Returns: 0 on success
+ */
+int drm_atomic_set_writeback_fb_for_connector(
+ struct drm_connector_state *conn_state,
+ struct drm_framebuffer *fb)
+{
+ struct drm_writeback_job *job =
+ drm_atomic_get_writeback_job(conn_state);
+ if (!job)
+ return -ENOMEM;
+
+ drm_framebuffer_assign(&job->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);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_atomic_set_writeback_fb_for_connector);
+
/**
* drm_atomic_add_affected_connectors - add connectors for crtc
* @state: atomic state
@@ -1702,6 +1815,8 @@ 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);
@@ -1724,6 +1839,15 @@ int drm_atomic_check_only(struct drm_atomic_state *state)
}
}
+ for_each_new_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 130da5195f3b6..dfd9cc6a2a3f6 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -30,6 +30,7 @@
#include <drm/drm_plane_helper.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_atomic_helper.h>
+#include <drm/drm_writeback.h>
#include <linux/dma-fence.h>
#include "drm_crtc_helper_internal.h"
@@ -1172,6 +1173,25 @@ void drm_atomic_helper_commit_modeset_disables(struct drm_device *dev,
}
EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_disables);
+static void drm_atomic_helper_commit_writebacks(struct drm_device *dev,
+ struct drm_atomic_state *old_state)
+{
+ struct drm_connector *connector;
+ struct drm_connector_state *new_conn_state;
+ int i;
+
+ for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
+ const struct drm_connector_helper_funcs *funcs;
+
+ funcs = connector->helper_private;
+
+ if (new_conn_state->writeback_job && new_conn_state->writeback_job->fb) {
+ WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK);
+ funcs->atomic_commit(connector, new_conn_state->writeback_job);
+ }
+ }
+}
+
/**
* drm_atomic_helper_commit_modeset_enables - modeset commit to enable outputs
* @dev: DRM device
@@ -1251,6 +1271,8 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
drm_bridge_enable(encoder->bridge);
}
+
+ drm_atomic_helper_commit_writebacks(dev, old_state);
}
EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables);
@@ -3660,6 +3682,9 @@ __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
if (state->crtc)
drm_connector_get(connector);
state->commit = NULL;
+
+ /* Don't copy over a writeback job, they are used only once */
+ state->writeback_job = NULL;
}
EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 9b9ba5d5ec0cb..d031e46ebffcf 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -87,6 +87,7 @@ 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)
@@ -249,7 +250,8 @@ int drm_connector_init(struct drm_device *dev,
config->num_connector++;
spin_unlock_irq(&config->connector_list_lock);
- 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 0000000000000..e5b8a4b79724b
--- /dev/null
+++ b/drivers/gpu/drm/drm_writeback.c
@@ -0,0 +1,245 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * (C) COPYRIGHT 2016 ARM Limited. All rights reserved.
+ * Author: Brian Starkey <[email protected]>
+ *
+ * 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_modeset_helper_vtables.h>
+#include <drm/drm_property.h>
+#include <drm/drm_writeback.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.
+ *
+ * A framebuffer may only be attached to a writeback connector when the
+ * connector is attached to a CRTC. The WRITEBACK_FB_ID property which sets the
+ * framebuffer applies only to a single commit (see below). A framebuffer may
+ * not be attached while the CRTC is off.
+ *
+ * Writeback connectors have some 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.
+ *
+ * "WRITEBACK_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.
+ */
+
+static int 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 -ENOMEM;
+ dev->mode_config.writeback_fb_id_property = prop;
+ }
+
+ if (!dev->mode_config.writeback_pixel_formats_property) {
+ prop = drm_property_create(dev, DRM_MODE_PROP_BLOB |
+ DRM_MODE_PROP_ATOMIC |
+ DRM_MODE_PROP_IMMUTABLE,
+ "WRITEBACK_PIXEL_FORMATS", 0);
+ if (!prop)
+ return -ENOMEM;
+ dev->mode_config.writeback_pixel_formats_property = prop;
+ }
+
+ return 0;
+}
+
+static const struct drm_encoder_funcs drm_writeback_encoder_funcs = {
+ .destroy = drm_encoder_cleanup,
+};
+
+/**
+ * drm_writeback_connector_init - Initialize a writeback connector and its properties
+ * @dev: DRM device
+ * @wb_connector: Writeback connector to initialize
+ * @con_funcs: Connector funcs vtable
+ * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
+ * @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. It will also create an internal encoder associated with the
+ * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for
+ * the encoder helper.
+ *
+ * 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_writeback_connector *wb_connector,
+ const struct drm_connector_funcs *con_funcs,
+ const struct drm_encoder_helper_funcs *enc_helper_funcs,
+ const u32 *formats, int n_formats)
+{
+ struct drm_property_blob *blob;
+ struct drm_connector *connector = &wb_connector->base;
+ struct drm_mode_config *config = &dev->mode_config;
+ int ret = create_writeback_properties(dev);
+
+ if (ret != 0)
+ return ret;
+
+ blob = drm_property_create_blob(dev, n_formats * sizeof(*formats),
+ formats);
+ if (IS_ERR(blob))
+ return PTR_ERR(blob);
+
+ drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
+ ret = drm_encoder_init(dev, &wb_connector->encoder,
+ &drm_writeback_encoder_funcs,
+ DRM_MODE_ENCODER_VIRTUAL, NULL);
+ if (ret)
+ goto fail;
+
+ connector->interlace_allowed = 0;
+
+ ret = drm_connector_init(dev, connector, con_funcs,
+ DRM_MODE_CONNECTOR_WRITEBACK);
+ if (ret)
+ goto connector_fail;
+
+ ret = drm_mode_connector_attach_encoder(connector,
+ &wb_connector->encoder);
+ if (ret)
+ goto attach_fail;
+
+ INIT_LIST_HEAD(&wb_connector->job_queue);
+ spin_lock_init(&wb_connector->job_lock);
+
+ drm_object_attach_property(&connector->base,
+ config->writeback_fb_id_property, 0);
+
+ drm_object_attach_property(&connector->base,
+ config->writeback_pixel_formats_property,
+ blob->base.id);
+ wb_connector->pixel_formats_blob_ptr = blob;
+
+ return 0;
+
+attach_fail:
+ drm_connector_cleanup(connector);
+connector_fail:
+ drm_encoder_cleanup(&wb_connector->encoder);
+fail:
+ drm_property_blob_put(blob);
+ return ret;
+}
+EXPORT_SYMBOL(drm_writeback_connector_init);
+
+/**
+ * drm_writeback_queue_job - Queue a writeback job for later signalling
+ * @wb_connector: The writeback connector to queue a job on
+ * @job: The job to queue
+ *
+ * This function adds a job to the job_queue for a writeback connector. It
+ * should be considered to take ownership of the writeback job, and so any other
+ * references to the job must be cleared after calling this function.
+ *
+ * Drivers must ensure that for a given writeback connector, jobs are queued in
+ * exactly the same order as they will be completed by the hardware (and
+ * signaled via drm_writeback_signal_completion).
+ *
+ * For every call to drm_writeback_queue_job() there must be exactly one call to
+ * drm_writeback_signal_completion()
+ *
+ * See also: drm_writeback_signal_completion()
+ */
+void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,
+ struct drm_writeback_job *job)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&wb_connector->job_lock, flags);
+ list_add_tail(&job->list_entry, &wb_connector->job_queue);
+ spin_unlock_irqrestore(&wb_connector->job_lock, flags);
+}
+EXPORT_SYMBOL(drm_writeback_queue_job);
+
+/*
+ * @cleanup_work: deferred cleanup of a writeback job
+ *
+ * The job cannot be cleaned up directly in drm_writeback_signal_completion,
+ * because it may be called in interrupt context. Dropping the framebuffer
+ * reference can sleep, and so the cleanup is deferred to a workqueue.
+ */
+static void cleanup_work(struct work_struct *work)
+{
+ struct drm_writeback_job *job = container_of(work,
+ struct drm_writeback_job,
+ cleanup_work);
+ drm_framebuffer_put(job->fb);
+ kfree(job);
+}
+
+
+/**
+ * drm_writeback_signal_completion - Signal the completion of a writeback job
+ * @wb_connector: The writeback connector whose job is complete
+ *
+ * Drivers should call this to signal the completion of a previously queued
+ * writeback job. It should be called as soon as possible after the hardware
+ * has finished writing, and may be called from interrupt context.
+ * It is the driver's responsibility to ensure that for a given connector, the
+ * hardware completes writeback jobs in the same order as they are queued.
+ *
+ * Unless the driver is holding its own reference to the framebuffer, it must
+ * not be accessed after calling this function.
+ *
+ * See also: drm_writeback_queue_job()
+ */
+void
+drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector)
+{
+ unsigned long flags;
+ struct drm_writeback_job *job;
+
+ spin_lock_irqsave(&wb_connector->job_lock, flags);
+ job = list_first_entry_or_null(&wb_connector->job_queue,
+ struct drm_writeback_job,
+ list_entry);
+ if (job)
+ list_del(&job->list_entry);
+ spin_unlock_irqrestore(&wb_connector->job_lock, flags);
+
+ if (WARN_ON(!job))
+ return;
+
+ INIT_WORK(&job->cleanup_work, cleanup_work);
+ queue_work(system_long_wq, &job->cleanup_work);
+}
+EXPORT_SYMBOL(drm_writeback_signal_completion);
diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index a57a8aa90ffb7..a5e904105db3a 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -594,6 +594,9 @@ void drm_atomic_set_fence_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);
+int drm_atomic_set_writeback_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 675cc3f8cf852..60c0ffb947d5e 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -429,6 +429,19 @@ struct drm_connector_state {
* protection. This is most commonly used for HDCP.
*/
unsigned int content_protection;
+
+ /**
+ * @writeback_job: Writeback job for writeback connectors
+ *
+ * Holds the framebuffer for a writeback connector. As the writeback
+ * completion may be asynchronous to the normal commit cycle, the
+ * writeback job lifetime is managed separately from the normal atomic
+ * state by this object.
+ *
+ * See also: drm_writeback_queue_job() and
+ * drm_writeback_signal_completion()
+ */
+ struct drm_writeback_job *writeback_job;
};
/**
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 33b3a96d66d0a..9ca32bf7bf183 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -779,6 +779,21 @@ struct drm_mode_config {
*/
struct drm_property *panel_orientation_property;
+ /**
+ * @writeback_fb_id_property: Property for writeback connectors, storing
+ * the ID of the output framebuffer.
+ * See also: drm_writeback_connector_init()
+ */
+ struct drm_property *writeback_fb_id_property;
+
+ /**
+ * @writeback_pixel_formats_property: Property for writeback connectors,
+ * storing an array of the supported pixel formats for the writeback
+ * engine (read-only).
+ * See also: drm_writeback_connector_init()
+ */
+ struct drm_property *writeback_pixel_formats_property;
+
/* dumb ioctl parameters */
uint32_t preferred_depth, prefer_shadow;
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index 35e2a3a79fc56..3b289773297c2 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -974,6 +974,17 @@ struct drm_connector_helper_funcs {
*/
int (*atomic_check)(struct drm_connector *connector,
struct drm_connector_state *state);
+
+ /**
+ * @atomic_commit:
+ *
+ * This hook is to be used by drivers implementing writeback connectors
+ * that need a point when to commit the writeback job to the hardware.
+ *
+ * This callback is used by the atomic modeset helpers.
+ */
+ void (*atomic_commit)(struct drm_connector *connector,
+ struct drm_writeback_job *writeback_job);
};
/**
diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
new file mode 100644
index 0000000000000..17cd1feecd7e5
--- /dev/null
+++ b/include/drm/drm_writeback.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * (C) COPYRIGHT 2016 ARM Limited. All rights reserved.
+ * Author: Brian Starkey <[email protected]>
+ *
+ * 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__
+#include <drm/drm_connector.h>
+#include <drm/drm_encoder.h>
+#include <linux/workqueue.h>
+
+struct drm_writeback_connector {
+ struct drm_connector base;
+
+ /**
+ * @encoder: Internal encoder used by the connector to fulfill
+ * the DRM framework requirements. The users of the
+ * @drm_writeback_connector control the behaviour of the @encoder
+ * by passing the @enc_funcs parameter to drm_writeback_connector_init()
+ * function.
+ */
+ struct drm_encoder encoder;
+
+ /**
+ * @pixel_formats_blob_ptr:
+ *
+ * DRM blob property data for the pixel formats list on writeback
+ * connectors
+ * See also drm_writeback_connector_init()
+ */
+ struct drm_property_blob *pixel_formats_blob_ptr;
+
+ /** @job_lock: Protects job_queue */
+ spinlock_t job_lock;
+
+ /**
+ * @job_queue:
+ *
+ * Holds a list of a connector's writeback jobs; the last item is the
+ * most recent. The first item may be either waiting for the hardware
+ * to begin writing, or currently being written.
+ *
+ * See also: drm_writeback_queue_job() and
+ * drm_writeback_signal_completion()
+ */
+ struct list_head job_queue;
+};
+
+struct drm_writeback_job {
+ /**
+ * @cleanup_work:
+ *
+ * Used to allow drm_writeback_signal_completion to defer dropping the
+ * framebuffer reference to a workqueue
+ */
+ struct work_struct cleanup_work;
+
+ /**
+ * @list_entry:
+ *
+ * List item for the writeback connector's @job_queue
+ */
+ struct list_head list_entry;
+
+ /**
+ * @fb:
+ *
+ * Framebuffer to be written to by the writeback connector. Do not set
+ * directly, use drm_atomic_set_writeback_fb_for_connector()
+ */
+ struct drm_framebuffer *fb;
+};
+
+int drm_writeback_connector_init(struct drm_device *dev,
+ struct drm_writeback_connector *wb_connector,
+ const struct drm_connector_funcs *con_funcs,
+ const struct drm_encoder_helper_funcs *enc_helper_funcs,
+ const u32 *formats, int n_formats);
+
+void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,
+ struct drm_writeback_job *job);
+
+void drm_writeback_cleanup_job(struct drm_writeback_job *job);
+void drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector);
+#endif
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 4b3a1bb58e680..3e6541f0400b8 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -344,6 +344,7 @@ enum drm_mode_subconnector {
#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 {
--
2.17.1
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.
Changelog:
- only accept the capability if the client has already set the
DRM_CLIENT_CAP_ATOMIC one.
Cc: Sean Paul <[email protected]>
Cc: Brian Starkey <[email protected]>
Signed-off-by: Liviu Dudau <[email protected]>
---
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 0d4cfb232576f..fe49fb0356b5a 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -334,6 +334,13 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
return -EINVAL;
file_priv->aspect_ratio_allowed = req->value;
break;
+ case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS:
+ if (!file_priv->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 027ac16da3d15..26485acc51d79 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -192,6 +192,13 @@ struct drm_file {
*/
unsigned aspect_ratio_allowed: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 9c660e1688abe..300f336633f28 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -687,6 +687,15 @@ struct drm_get_cap {
*/
#define DRM_CLIENT_CAP_ASPECT_RATIO 4
+/**
+ * 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 5
+
/** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
struct drm_set_client_cap {
__u64 capability;
--
2.17.1
Hi Liviu,
On Tue, Jun 12, 2018 at 02:52:33PM +0100, Liviu Dudau wrote:
>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.
>
>Changelog:
> - only accept the capability if the client has already set the
>DRM_CLIENT_CAP_ATOMIC one.
>
>Cc: Sean Paul <[email protected]>
>Cc: Brian Starkey <[email protected]>
>Signed-off-by: Liviu Dudau <[email protected]>
LGTM,
Reviewed-by: Brian Starkey <[email protected]>
Thanks,
-Brian
>---
> 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 0d4cfb232576f..fe49fb0356b5a 100644
>--- a/drivers/gpu/drm/drm_ioctl.c
>+++ b/drivers/gpu/drm/drm_ioctl.c
>@@ -334,6 +334,13 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
> return -EINVAL;
> file_priv->aspect_ratio_allowed = req->value;
> break;
>+ case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS:
>+ if (!file_priv->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 027ac16da3d15..26485acc51d79 100644
>--- a/include/drm/drm_file.h
>+++ b/include/drm/drm_file.h
>@@ -192,6 +192,13 @@ struct drm_file {
> */
> unsigned aspect_ratio_allowed: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 9c660e1688abe..300f336633f28 100644
>--- a/include/uapi/drm/drm.h
>+++ b/include/uapi/drm/drm.h
>@@ -687,6 +687,15 @@ struct drm_get_cap {
> */
> #define DRM_CLIENT_CAP_ASPECT_RATIO 4
>
>+/**
>+ * 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 5
>+
> /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
> struct drm_set_client_cap {
> __u64 capability;
>--
>2.17.1
>