[PATCH 06/13] drm: add atomic hook to read property plus helper

[Rob Clark]

On Wed, Dec 17, 2014 at 9:06 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
> On Wed, Dec 17, 2014 at 03:02:41PM +0100, Daniel Vetter wrote:
>> On Tue, Dec 16, 2014 at 06:05:34PM -0500, Rob Clark wrote:
>> > Once a driver is using atomic helpers for modeset, the next step is to
>> > switch over to atomic properties.  To do this, plug in the helper
>> > function to your modeconfig funcs and be sure to implement the plane/
>> > crtc/connector atomic_{get,set}_property vfuncs for any of your mode-
>> > objects which have driver custom properties.
>> >
>> > Signed-off-by: Rob Clark <robdclark at gmail.com>
>> > ---
>> >  drivers/gpu/drm/drm_atomic_helper.c | 46 +++++++++++++++++++++++++++++++++++++
>> >  drivers/gpu/drm/drm_crtc.c          |  9 ++++++++
>> >  include/drm/drm_atomic_helper.h     |  2 ++
>> >  include/drm/drm_crtc.h              |  3 +++
>> >  4 files changed, 60 insertions(+)
>> >
>> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
>> > index d42fdb1..1a1ab34 100644
>> > --- a/drivers/gpu/drm/drm_atomic_helper.c
>> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
>> > @@ -1703,6 +1703,52 @@ backoff:
>> >  EXPORT_SYMBOL(drm_atomic_helper_connector_set_property);
>> >
>> >  /**
>> > + * drm_atomic_helper_get_property - helper to read atomic property
>> > + * @obj: drm mode object whose property to read
>> > + * @property: the property to read
>> > + * @val: the read value, returned by reference
>> > + *
>> > + * RETURNS:
>> > + * Zero on success, error code on failure
>> > + */
>> > +int drm_atomic_helper_get_property(struct drm_mode_object *obj,
>> > +           struct drm_property *property, uint64_t *val)
>> > +{
>> > +   struct drm_device *dev = property->dev;
>> > +   int ret;
>> > +
>> > +   switch (obj->type) {
>> > +   case DRM_MODE_OBJECT_CONNECTOR: {
>> > +           struct drm_connector *connector = obj_to_connector(obj);
>> > +           WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
>> > +           ret = connector->funcs->atomic_get_property(connector,
>> > +                           connector->state, property, val);
>>
>> Shouldn't we use the get helpers introduced in previous patches here? For
>> legacy support we definitely want old core stuff like dpms to keep
>> working. Of course that means all the new atomic properties won't get
>> magically filtered out. But I think we need to hide them explicitly
>> anyway, e.g. with a new DRM_MODE_PROP_ATOMIC and checking for that in
>> legacy paths.
>
> Also I'm not sure if there's a benefit to make this a vfunc+helper instead
> of just core code called unconditionally. Meaning I can't think of any
> case where drivers want to overwrite this, ever. They can do all the fancy
> they want for their private properties in the per-object hooks. And for
> core/shared stuff we better not allow them to play with fire.
>
> Or do I miss an important case here?

drivers can have their own custom properties too :-)

umm, or are you talking about the vfunc in config->funcs?  (In which
case, it was at least a convenient way to for core to know whether to
take legacy path or atomic path)

BR,
-R

> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch