[PATCH v5 14/19] drm: writeback: Add job prepare and cleanup operations
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Feb 27 12:38:56 UTC 2019
Hi Liviu,
On Tue, Feb 26, 2019 at 06:39:40PM +0000, Liviu Dudau wrote:
> On Thu, Feb 21, 2019 at 12:32:07PM +0200, Laurent Pinchart wrote:
> > As writeback jobs contain a framebuffer, drivers may need to prepare and
> > cleanup them the same way they can prepare and cleanup framebuffers for
> > planes. Add two new optional connector helper operations,
> > .prepare_writeback_job() and .cleanup_writeback_job() to support this.
>
> I'm having a bit of a hard time parsing the above paragraph. I think that
> what you are saying is that you need to prepare and cleanup the framebuffers that
> writeback jobs have, but it also can be read that you need to prepare/cleanup
> the actual jobs. If the latter, then I'm curious to know what is special
> about the jobs that you need preparing/cleaning up.
I meant the framebuffers, but I wouldn't be surprised if the jobs were
later extended with more fields that would require similar preparation.
That's why I think prepare/cleanup job operations make sense.
> > The job prepare operation is called from
> > drm_atomic_helper_prepare_planes() to avoid a new atomic commit helper
> > that would need to be called by all drivers not using
> > drm_atomic_helper_commit(). The job cleanup operation is called from the
> > existing drm_writeback_cleanup_job() function, invoked both when
> > destroying the job as part of a aborted commit, or when the job
> > completes.
> >
> > The drm_writeback_job structure is extended with a priv field to let
> > drivers store per-job data, such as mappings related to the writeback
> > framebuffer.
>
> Could the driver store in this priv field a structure that contains the
> connector, whereby removing the need for a back-pointer?
The priv field points to an opaque structure, forcing drivers to use a
standard structure there would make the API more complex in my opinion,
without any added value I can see.
> > For internal plumbing reasons the drm_writeback_job structure needs to
> > store a back-pointer to the drm_writeback_connector. To avoid pushing
> > too much writeback-specific knowledge to drm_atomic_uapi.c, create a
> > drm_writeback_set_fb() function, move the writeback job setup code
> > there, and set the connector backpointer. The prepare_signaling()
> > function doesn't need to allocate writeback jobs and can ignore
> > connectors without a job, as it is called after the writeback jobs are
> > allocated to store framebuffers, and a writeback fence with a
> > framebuffer is an invalid configuration that gets rejected by the commit
> > check.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> > ---
> > drivers/gpu/drm/drm_atomic_helper.c | 11 ++++++
> > drivers/gpu/drm/drm_atomic_uapi.c | 31 +++++------------
> > drivers/gpu/drm/drm_writeback.c | 43 ++++++++++++++++++++++++
> > include/drm/drm_modeset_helper_vtables.h | 7 ++++
> > include/drm/drm_writeback.h | 28 ++++++++++++++-
> > 5 files changed, 96 insertions(+), 24 deletions(-)
> >
> > This patch is currently missing documentation for the
> > .prepare_writeback_job() and .cleanup_writeback_job() operations. I plan
> > to fix this, but first wanted feedback on the direction taken. I'm not
> > entirely happy with the priv pointer in the drm_writeback_job structure,
> > but adding a full state duplicate/destroy machinery for that structure
> > was equally unappealing to me.
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index 6fe2303fccd9..70a4886c6e65 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -2245,10 +2245,21 @@ EXPORT_SYMBOL(drm_atomic_helper_commit_cleanup_done);
> > int drm_atomic_helper_prepare_planes(struct drm_device *dev,
> > struct drm_atomic_state *state)
> > {
> > + struct drm_connector *connector;
> > + struct drm_connector_state *new_conn_state;
> > struct drm_plane *plane;
> > struct drm_plane_state *new_plane_state;
> > int ret, i, j;
> >
> > + for_each_new_connector_in_state(state, connector, new_conn_state, i) {
> > + if (!new_conn_state->writeback_job)
> > + continue;
> > +
> > + ret = drm_writeback_prepare_job(new_conn_state->writeback_job);
> > + if (ret < 0)
> > + return ret;
> > + }
> > +
> > for_each_new_plane_in_state(state, plane, new_plane_state, i) {
> > const struct drm_plane_helper_funcs *funcs;
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
> > index c40889888a16..e802152a01ad 100644
> > --- a/drivers/gpu/drm/drm_atomic_uapi.c
> > +++ b/drivers/gpu/drm/drm_atomic_uapi.c
> > @@ -647,28 +647,15 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
> > return 0;
> > }
> >
> > -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;
> > -}
> > -
> > static 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;
> > + int ret;
> >
> > - drm_framebuffer_assign(&job->fb, fb);
> > + ret = drm_writeback_set_fb(conn_state, fb);
> > + if (ret < 0)
> > + return ret;
> >
> > if (fb)
> > DRM_DEBUG_ATOMIC("Set [FB:%d] for connector state %p\n",
> > @@ -1158,19 +1145,17 @@ static int prepare_signaling(struct drm_device *dev,
> >
> > for_each_new_connector_in_state(state, conn, conn_state, i) {
> > struct drm_writeback_connector *wb_conn;
> > - struct drm_writeback_job *job;
> > struct drm_out_fence_state *f;
> > struct dma_fence *fence;
> > s32 __user *fence_ptr;
> >
> > + if (!conn_state->writeback_job)
> > + continue;
> > +
> > 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)
> > @@ -1192,7 +1177,7 @@ static int prepare_signaling(struct drm_device *dev,
> > return ret;
> > }
> >
> > - job->out_fence = fence;
> > + conn_state->writeback_job->out_fence = fence;
> > }
> >
> > /*
> > diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> > index afb1ae6e0ecb..4678d61d634a 100644
> > --- a/drivers/gpu/drm/drm_writeback.c
> > +++ b/drivers/gpu/drm/drm_writeback.c
> > @@ -239,6 +239,42 @@ int drm_writeback_connector_init(struct drm_device *dev,
> > }
> > EXPORT_SYMBOL(drm_writeback_connector_init);
> >
> > +int drm_writeback_set_fb(struct drm_connector_state *conn_state,
> > + struct drm_framebuffer *fb)
> > +{
> > + 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);
> > + if (!conn_state->writeback_job)
> > + return -ENOMEM;
> > +
> > + conn_state->writeback_job->connector =
> > + drm_connector_to_writeback(conn_state->connector);
> > + }
> > +
> > + drm_framebuffer_assign(&conn_state->writeback_job->fb, fb);
> > + return 0;
> > +}
> > +
> > +int drm_writeback_prepare_job(struct drm_writeback_job *job)
> > +{
> > + struct drm_writeback_connector *connector = job->connector;
> > + const struct drm_connector_helper_funcs *funcs =
> > + connector->base.helper_private;
> > + int ret;
> > +
> > + if (funcs->cleanup_writeback_job) {
>
> This feels weird, did you mean to actually check that the funcs->prepare_writeback_job
> hook is implemented?
Good catch. I'll fix this.
> Otherwise, things look good to me!
Thank you.
> > + ret = funcs->prepare_writeback_job(connector, job);
> > + if (ret < 0)
> > + return ret;
> > + }
> > +
> > + job->prepared = true;
> > + return 0;
> > +}
> > +
> > /**
> > * drm_writeback_queue_job - Queue a writeback job for later signalling
> > * @wb_connector: The writeback connector to queue a job on
> > @@ -275,6 +311,13 @@ EXPORT_SYMBOL(drm_writeback_queue_job);
> >
> > void drm_writeback_cleanup_job(struct drm_writeback_job *job)
> > {
> > + struct drm_writeback_connector *connector = job->connector;
> > + const struct drm_connector_helper_funcs *funcs =
> > + connector->base.helper_private;
> > +
> > + if (job->prepared && funcs->cleanup_writeback_job)
> > + funcs->cleanup_writeback_job(connector, job);
> > +
> > if (job->fb)
> > drm_framebuffer_put(job->fb);
> >
> > diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
> > index 61142aa0ab23..73d03fe66799 100644
> > --- a/include/drm/drm_modeset_helper_vtables.h
> > +++ b/include/drm/drm_modeset_helper_vtables.h
> > @@ -49,6 +49,8 @@
> > */
> >
> > enum mode_set_atomic;
> > +struct drm_writeback_connector;
> > +struct drm_writeback_job;
> >
> > /**
> > * struct drm_crtc_helper_funcs - helper operations for CRTCs
> > @@ -989,6 +991,11 @@ struct drm_connector_helper_funcs {
> > */
> > void (*atomic_commit)(struct drm_connector *connector,
> > struct drm_connector_state *state);
> > +
> > + int (*prepare_writeback_job)(struct drm_writeback_connector *connector,
> > + struct drm_writeback_job *job);
> > + void (*cleanup_writeback_job)(struct drm_writeback_connector *connector,
> > + struct drm_writeback_job *job);
> > };
> >
> > /**
> > diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
> > index 47662c362743..777c14c847f0 100644
> > --- a/include/drm/drm_writeback.h
> > +++ b/include/drm/drm_writeback.h
> > @@ -79,6 +79,20 @@ struct drm_writeback_connector {
> > };
> >
> > struct drm_writeback_job {
> > + /**
> > + * @connector:
> > + *
> > + * Back-pointer to the writeback connector associated with the job
> > + */
> > + struct drm_writeback_connector *connector;
> > +
> > + /**
> > + * @prepared:
> > + *
> > + * Set when the job has been prepared with drm_writeback_prepare_job()
> > + */
> > + bool prepared;
> > +
> > /**
> > * @cleanup_work:
> > *
> > @@ -98,7 +112,7 @@ struct drm_writeback_job {
> > * @fb:
> > *
> > * Framebuffer to be written to by the writeback connector. Do not set
> > - * directly, use drm_atomic_set_writeback_fb_for_connector()
> > + * directly, use drm_writeback_set_fb()
> > */
> > struct drm_framebuffer *fb;
> >
> > @@ -108,6 +122,13 @@ struct drm_writeback_job {
> > * Fence which will signal once the writeback has completed
> > */
> > struct dma_fence *out_fence;
> > +
> > + /**
> > + * @priv:
> > + *
> > + * Driver-private data
> > + */
> > + void *priv;
> > };
> >
> > static inline struct drm_writeback_connector *
> > @@ -122,6 +143,11 @@ int drm_writeback_connector_init(struct drm_device *dev,
> > const struct drm_encoder_helper_funcs *enc_helper_funcs,
> > const u32 *formats, int n_formats);
> >
> > +int drm_writeback_set_fb(struct drm_connector_state *conn_state,
> > + struct drm_framebuffer *fb);
> > +
> > +int drm_writeback_prepare_job(struct drm_writeback_job *job);
> > +
> > void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector,
> > struct drm_connector_state *conn_state);
> >
--
Regards,
Laurent Pinchart
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