Re: [PATCH] drm/omap: Rework the rotation-on-crtc hack

[Maarten Lankhorst <maarten.lankhorst@linux.intel.com>]

Op 31-07-17 om 17:42 schreef Daniel Vetter:
> I want/need to rework the core property handling, and this hack is
> getting in the way. But since it's a non-standard propety only used by
> legacy userspace we know that this will only every be called from
> ioctl code. And never on some other free-standing state struct, where
> this old hack wouldn't work either.
>
> v2: don't forget zorder and get_property!
>
> v3: Shadow the legacy state to avoid locking issues in get_property
> (Maarten).
>
> v4: Review from Laurent
> - Move struct omap_crtc_state into omap_crtc.c
> - Clean up comments.
> - Don't forget to copy the shadowed state over on duplicate.
>
> v5: Don't forget to update the reset handler (Maarten).
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> (v4)
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  drivers/gpu/drm/omapdrm/omap_crtc.c | 109 ++++++++++++++++++++++++------------
>  1 file changed, 72 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
> index 14e8a7738b06..9014085c33df 100644
> --- a/drivers/gpu/drm/omapdrm/omap_crtc.c
> +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
> @@ -26,6 +26,16 @@
>  
>  #include "omap_drv.h"
>  
> +#define to_omap_crtc_state(x) container_of(x, struct omap_crtc_state, base)
> +
> +struct omap_crtc_state {
> +	/* Must be first. */
> +	struct drm_crtc_state base;
> +	/* Shadow values for legacy userspace support. */
> +	unsigned int rotation;
> +	unsigned int zpos;
> +};
> +
>  #define to_omap_crtc(x) container_of(x, struct omap_crtc, base)
>  
>  struct omap_crtc {
> @@ -498,39 +508,35 @@ static void omap_crtc_atomic_flush(struct drm_crtc *crtc,
>  	spin_unlock_irq(&crtc->dev->event_lock);
>  }
>  
> -static bool omap_crtc_is_plane_prop(struct drm_crtc *crtc,
> -	struct drm_property *property)
> -{
> -	struct drm_device *dev = crtc->dev;
> -	struct omap_drm_private *priv = dev->dev_private;
> -
> -	return property == priv->zorder_prop ||
> -		property == crtc->primary->rotation_property;
> -}
> -
>  static int omap_crtc_atomic_set_property(struct drm_crtc *crtc,
>  					 struct drm_crtc_state *state,
>  					 struct drm_property *property,
>  					 uint64_t val)
>  {
> -	if (omap_crtc_is_plane_prop(crtc, property)) {
> -		struct drm_plane_state *plane_state;
> -		struct drm_plane *plane = crtc->primary;
> -
> -		/*
> -		 * Delegate property set to the primary plane. Get the plane
> -		 * state and set the property directly.
> -		 */
> -
> -		plane_state = drm_atomic_get_plane_state(state->state, plane);
> -		if (IS_ERR(plane_state))
> -			return PTR_ERR(plane_state);
> +	struct omap_drm_private *priv = crtc->dev->dev_private;
> +	struct omap_crtc_state *omap_state = to_omap_crtc_state(state);
> +	struct drm_plane_state *plane_state;
>  
> -		return drm_atomic_plane_set_property(plane, plane_state,
> -				property, val);
> +	/*
> +	 * Delegate property set to the primary plane. Get the plane state and
> +	 * set the property directly, but keep a shadow copy for the
> +	 * atomic_get_property callback.
> +	 */
> +	plane_state = drm_atomic_get_plane_state(state->state, crtc->primary);
> +	if (IS_ERR(plane_state))
> +		return PTR_ERR(plane_state);
> +
> +	if (property == crtc->primary->rotation_property) {
> +		plane_state->rotation = val;
> +		omap_state->rotation = val;
> +	} else if (property == priv->zorder_prop) {
> +		plane_state->zpos = val;
> +		omap_state->zpos = val;
With atomic we should try to always make the getprop values accurate, or compositors might have
troubles restoring.

I would update the shadow values in omap_crtc_atomic_check through omap_crtc_atomic_check instead,
with something like this:

+       pri_state = drm_atomic_get_new_plane_state(crtc->primary, state->state);
+       if (pri_state) {
+               struct omap_crtc_state *omap_crtc_state =
+                       to_omap_crtc_state(state);
+
+               omap_crtc_state->zpos = pri_state->zpos;
+               omap_crtc_state->rotation = pri_state->rotation;
+       }

That way even when updating the property through the primary plane, it gets reflected correctly. For example when vt switching
with fbdev.

> +	} else {
> +		return -EINVAL;
>  	}
>  
> -	return -EINVAL;
> +	return 0;
>  }
>  
>  static int omap_crtc_atomic_get_property(struct drm_crtc *crtc,
> @@ -538,28 +544,57 @@ static int omap_crtc_atomic_get_property(struct drm_crtc *crtc,
>  					 struct drm_property *property,
>  					 uint64_t *val)
>  {
> -	if (omap_crtc_is_plane_prop(crtc, property)) {
> -		/*
> -		 * Delegate property get to the primary plane. The
> -		 * drm_atomic_plane_get_property() function isn't exported, but
> -		 * can be called through drm_object_property_get_value() as that
> -		 * will call drm_atomic_get_property() for atomic drivers.
> -		 */
> -		return drm_object_property_get_value(&crtc->primary->base,
> -				property, val);
> -	}
> +	struct omap_drm_private *priv = crtc->dev->dev_private;
> +	struct omap_crtc_state *omap_state = to_omap_crtc_state(state);
> +
> +	if (property == crtc->primary->rotation_property)
> +		return omap_state->rotation;
> +	else if (property == priv->zorder_prop)
> +		return omap_state->zpos;
>  
>  	return -EINVAL;
>  }
>  
> +static void omap_crtc_reset(struct drm_crtc *crtc)
> +{
> +	if (crtc->state)
> +		__drm_atomic_helper_crtc_destroy_state(crtc->state);
> +
> +	kfree(crtc->state);
> +	crtc->state = kzalloc(sizeof(struct omap_crtc_state), GFP_KERNEL);
> +
> +	if (crtc->state)
> +		crtc->state->crtc = crtc;
Hm, perhaps add a __drm_atomic_helper_crtc_reset, and (perhaps) for planes too?

Similar to __drm_atomic_helper_connector_reset, in case we want to add something in the future that might need to be initialised. :)
> +}
> +
> +static struct drm_crtc_state *
> +omap_crtc_duplicate_state(struct drm_crtc *crtc)
> +{
> +	struct omap_crtc_state *state, *current_state;
> +
> +	if (WARN_ON(!crtc->state))
> +		return NULL;
> +
> +	current_state = to_omap_crtc_state(crtc->state);
> +
> +	state = kmalloc(sizeof(*state), GFP_KERNEL);
> +	if (state)
> +		__drm_atomic_helper_crtc_duplicate_state(crtc, &state->base);
> +
> +	state->zpos = current_state->zpos;
> +	state->rotation = current_state->rotation;
> +
> +	return &state->base;
> +}
> +
>  static const struct drm_crtc_funcs omap_crtc_funcs = {
> -	.reset = drm_atomic_helper_crtc_reset,
> +	.reset = omap_crtc_reset,
>  	.set_config = drm_atomic_helper_set_config,
>  	.destroy = omap_crtc_destroy,
>  	.page_flip = drm_atomic_helper_page_flip,
>  	.gamma_set = drm_atomic_helper_legacy_gamma_set,
>  	.set_property = drm_atomic_helper_crtc_set_property,
> -	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
> +	.atomic_duplicate_state = omap_crtc_duplicate_state,
>  	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
>  	.atomic_set_property = omap_crtc_atomic_set_property,
>  	.atomic_get_property = omap_crtc_atomic_get_property,


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