On Wed, 2017-01-25 at 06:59 +0100, Daniel Vetter wrote:
> On Tue, Jan 24, 2017 at 03:49:32PM -0800, Dhinakaran Pandiyan wrote:
> > It is necessary to track states for objects other than connector, crtc
> > and plane for atomic modesets. But adding objects like DP MST link
> > bandwidth to drm_atomic_state would mean that a non-core object will be
> > modified by the core helper functions for swapping and clearing
> > it's state. So, lets add void * objects and helper functions that operate
> > on void * types to keep these objects and states private to the core.
> > Drivers can then implement specific functions to swap and clear states.
> > The other advantage having just void * for these objects in
> > drm_atomic_state is that objects of different types can be managed in the
> > same state array.
> >
> > Suggested-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
>
> I think an overview DOC: section to explain how to subclass atomic state
> and how to do private state objects would be great. But I can do that once
> your patch has landed, since it'd be much more about the overall design of
> atomic (and I promised to do that anyway).
>
> Looks pretty good, a few nits below still. I'll also ask amd folks to
> check this out, and I think Ville could use it for his cdclk stuff.
>
> > ---
> > drivers/gpu/drm/drm_atomic.c | 55 +++++++++++++++++++++++++++++++++++++
> > drivers/gpu/drm/drm_atomic_helper.c | 6 ++++
> > include/drm/drm_atomic.h | 30 ++++++++++++++++++++
> > 3 files changed, 91 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> > index 723392f..f3a71cc 100644
> > --- a/drivers/gpu/drm/drm_atomic.c
> > +++ b/drivers/gpu/drm/drm_atomic.c
> > @@ -57,6 +57,7 @@ void drm_atomic_state_default_release(struct drm_atomic_state *state)
> > kfree(state->connectors);
> > kfree(state->crtcs);
> > kfree(state->planes);
> > + kfree(state->private_objs);
> > }
> > EXPORT_SYMBOL(drm_atomic_state_default_release);
> >
> > @@ -184,6 +185,20 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
> > state->planes[i].ptr = NULL;
> > state->planes[i].state = NULL;
> > }
> > +
> > + for (i = 0; i < state->num_private_objs; i++) {
> > + void *priv_obj = state->private_objs[i].obj;
> > + void *obj_state = state->private_objs[i].obj_state;
> > +
> > + if (!priv_obj)
> > + continue;
> > +
> > + state->private_objs[i].funcs->destroy_state(obj_state);
> > + state->private_objs[i].obj = NULL;
> > + state->private_objs[i].obj_state = NULL;
> > + state->private_objs[i].funcs = NULL;
> > + }
> > +
> > }
> > EXPORT_SYMBOL(drm_atomic_state_default_clear);
> >
> > @@ -976,6 +991,46 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,
> > plane->funcs->atomic_print_state(p, state);
> > }
> >
> > +
>
> Needs kerneldoc here.
>
> > +void *
> > +drm_atomic_get_priv_obj_state(struct drm_atomic_state *state, void *obj,
>
> ocd bikeshed: priv_obj vs private_obj inconsistency here, please stick to
> one (I don't care which one).
>
> > + const struct drm_private_state_funcs *funcs)
> > +{
> > + int index, num_objs, i;
> > + size_t size;
> > + struct __drm_private_objs_state *arr;
> > +
> > + for (i = 0; i < state->num_private_objs; i++)
> > + if (obj == state->private_objs[i].obj &&
> > + state->private_objs[i].obj_state)
> > + return state->private_objs[i].obj_state;
> > +
> > + num_objs = state->num_private_objs + 1;
> > + size = sizeof(*state->private_objs) * num_objs;
> > + arr = krealloc(state->private_objs, size, GFP_KERNEL);
> > + if (!arr)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + state->private_objs = arr;
> > + index = state->num_private_objs;
> > + memset(&state->private_objs[index], 0, sizeof(*state->private_objs));
> > +
> > + state->private_objs[index].obj_state = funcs->duplicate_state(state, obj);
> > + if (!state->private_objs[index].obj_state)
> > + return ERR_PTR(-ENOMEM);
>
> I wondered whether we need to allow other error codes than ENOMEM, e.g.
> if duplicate_state needs to acquire a ww_mutex. But we can always acquire
> the necessary locks outside of drm_atomic_get_priv_obj_state in some
> helper/driver wrapper. So no big deal, but worth explaining that
> drm_atomic_get_priv_obj_state won't acquire necessarily locsk (since it
> doesn't know about them) in the kernel-doc.
>
Got it, will include that.
> > +
> > + state->private_objs[index].obj = obj;
> > + state->private_objs[index].funcs = funcs;
> > + state->num_private_objs = num_objs;
> > +
> > + DRM_DEBUG_ATOMIC("Added new private object state %p to %p\n",
> > + state->private_objs[index].obj_state, state);
> > +
> > + return state->private_objs[index].obj_state;
> > +}
> > +EXPORT_SYMBOL(drm_atomic_get_priv_obj_state);
> > +
> > +
> > /**
> > * drm_atomic_get_connector_state - get connector state
> > * @state: global atomic state object
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index 1f0cd7e..dd34d21 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -1977,6 +1977,8 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
> > struct drm_plane *plane;
> > struct drm_plane_state *plane_state;
> > struct drm_crtc_commit *commit;
> > + void *obj, *obj_state;
> > + const struct drm_private_state_funcs *funcs;
> >
> > if (stall) {
> > for_each_crtc_in_state(state, crtc, crtc_state, i) {
> > @@ -2025,6 +2027,10 @@ void drm_atomic_helper_swap_state(struct drm_atomic_state *state,
> > swap(state->planes[i].state, plane->state);
> > plane->state->state = NULL;
> > }
> > +
> > + for_each_private_obj(state, obj, obj_state, i, funcs) {
> > + funcs->swap_state(obj, &state->private_objs[i].obj_state);
> > + }
> > }
> > EXPORT_SYMBOL(drm_atomic_helper_swap_state);
> >
> > diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
> > index f1cb2b0..80d6e21 100644
> > --- a/include/drm/drm_atomic.h
> > +++ b/include/drm/drm_atomic.h
> > @@ -153,6 +153,18 @@ struct __drm_connnectors_state {
> > struct drm_connector_state *state;
> > };
> >
>
> This one needs kernel-doc too, since it's a struct that drivers/helpers
> will need to implement. Please use the inline style and document expected
> semantics in detail, like we do for other vfunc tables.
>
> > +struct drm_private_state_funcs {
>
> I also wonder whether we shouldn't give this a drm_atomic_ prefix ...
>
> > + void (*swap_state)(void *obj, void **obj_state_ptr);
> > + void (*destroy_state)(void *obj_state);
> > + void *(*duplicate_state)(struct drm_atomic_state *state, void *obj);
> > +};
> > +
> > +struct __drm_private_objs_state {
> > + void *obj;
> > + void *obj_state;
> > + const struct drm_private_state_funcs *funcs;
> > +};
> > +
> > /**
> > * struct drm_atomic_state - the global state object for atomic updates
> > * @ref: count of all references to this state (will not be freed until zero)
> > @@ -164,6 +176,8 @@ struct __drm_connnectors_state {
> > * @crtcs: pointer to array of CRTC pointers
> > * @num_connector: size of the @connectors and @connector_states arrays
> > * @connectors: pointer to array of structures with per-connector data
> > + * @num_private_objs: size of the @private_objs array
> > + * @private_objs: pointer to array of private object pointers
> > * @acquire_ctx: acquire context for this atomic modeset state update
> > */
> > struct drm_atomic_state {
> > @@ -177,6 +191,8 @@ struct drm_atomic_state {
> > struct __drm_crtcs_state *crtcs;
> > int num_connector;
> > struct __drm_connnectors_state *connectors;
> > + int num_private_objs;
> > + struct __drm_private_objs_state *private_objs;
> >
> > struct drm_modeset_acquire_ctx *acquire_ctx;
> >
> > @@ -269,6 +285,11 @@ int drm_atomic_connector_set_property(struct drm_connector *connector,
> > struct drm_connector_state *state, struct drm_property *property,
> > uint64_t val);
> >
> > +void * __must_check
> > +drm_atomic_get_priv_obj_state(struct drm_atomic_state *state,
> > + void *obj,
> > + const struct drm_private_state_funcs *funcs);
> > +
> > /**
> > * drm_atomic_get_existing_crtc_state - get crtc state, if it exists
> > * @state: global atomic state object
> > @@ -413,6 +434,15 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
> > (__i)++) \
> > for_each_if (plane_state)
> >
> > +#define for_each_private_obj(__state, obj, obj_state, __i, __funcs) \
> > + for ((__i) = 0; \
> > + (__i) < (__state)->num_private_objs && \
> > + ((obj) = (__state)->private_objs[__i].obj, \
> > + (__funcs) = (__state)->private_objs[__i].funcs, \
> > + (obj_state) = (__state)->private_objs[__i].obj_state, 1); \
> > + (__i)++) \
> > + for_each_if (__funcs)
>
> You are not filtering for the function table here, which is important to
> make sure that this can be used to only walk over objects with a given
> vtable. With that we can then #define specific macros for e.g. mst:
>
> struct drm_private_state_funcs mst_state_funcs;
>
> #define for_each_mst_state(__state, obj, obj_state, __i, __funcs) \
> for_each_private_obj(__state, &mst_state_funcs, obj, obj_state, __i, __funcs)
>
> I'd place the vfunc right after the state, since those are both input
> parameters to the macro, and specify what exactly we're looping over. To
> make this work you need something like:
>
> #define for_each_private_obj(__state, obj_funcs, obj, obj_state, __i, __funcs) \
> for ((__i) = 0; \
> (__i) < (__state)->num_private_objs && \
> ((obj) = (__state)->private_objs[__i].obj, \
> (__funcs) = (__state)->private_objs[__i].funcs, \
> (obj_state) = (__state)->private_objs[__i].obj_state, 1); \
> (__i)++) \
> for_each_if (__funcs == obj_funcs)
>
> Note the check to compare __funcs == obj_funcs.
>
> With that other subsytem can the filter for their own objects only with
> e.g.
>
> #define intel_for_each_cdclk_state(__state, obj, obj_state, __i, __funcs) \
> for_each_private_obj(__state, &intel_cdclk_state_funcs, obj, obj_state, __i, __funcs)
>
> Would be good to also then have kerneldoc for this iterator, to explain
> how to use it.
> -Daniel
>
I see your point but we can't use this iterator in the swap_state()
helper if we do that. I have used it to swap states for all objects
using this version without filtering.
I guess, I can just code the iterator explicitly for swap_state() and
re-write the iterator with the filtering.
-DK
> > /**
> > * drm_atomic_crtc_needs_modeset - compute combined modeset need
> > * @state: &drm_crtc_state for the CRTC
> > --
> > 2.7.4
> >
>
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