Re: [PATCH v2 05/20] drm/colorop: Create drm_atomic_helper_colorop_create_state()

[Thomas Zimmermann <tzimmermann@suse.de>]

Am 20.03.26 um 17:27 schrieb Maxime Ripard:
> Commit 47b5ac7daa46 ("drm/atomic: Add new atomic_create_state callback
> to drm_private_obj") introduced a new pattern for allocating drm object
> states.
>
> Instead of relying on the reset() callback, it created a new
> atomic_create_state hook. This is helpful because reset is a bit
> overloaded: it's used to create the initial software state, reset it,
> but also reset the hardware.
>
> It can also be used either at probe time, to create the initial state
> and possibly reset the hardware to an expected default, but also during
> suspend/resume.
>
> Both these cases come with different expectations too: during the
> initialization, we want to initialize all states, but during
> suspend/resume, drm_private_states for example are expected to be kept
> around.
>
> And reset() isn't fallible, which makes it harder to handle
> initialization errors properly.
>
> It's also only relevant for some drivers, since all the helpers for
> reset only create a new state, and don't touch the hardware at all.
>
> It was thus decided to create a new hook that would allocate and
> initialize a pristine state without any side effect: atomic_create_state
> to untangle a bit some of it, and to separate the
> initialization with the actual reset one might need during a
> suspend/resume.
>
> Let's continue the transition to the new pattern with drm_colorop.
>
> Signed-off-by: Maxime Ripard <mripard@kernel.org>

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

> ---
>   drivers/gpu/drm/drm_colorop.c | 23 +++++++++++++++++++++++
>   include/drm/drm_colorop.h     |  2 ++
>   2 files changed, 25 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_colorop.c b/drivers/gpu/drm/drm_colorop.c
> index 6a26b83b260e8d8e83c703ecde490a7a8740ebfb..7bfaf2617ec315f42d80ac72a5eaaef868e65657 100644
> --- a/drivers/gpu/drm/drm_colorop.c
> +++ b/drivers/gpu/drm/drm_colorop.c
> @@ -521,10 +521,33 @@ static void __drm_colorop_state_init(struct drm_colorop_state *colorop_state,
>   						      &val);
>   		colorop_state->curve_1d_type = val;
>   	}
>   }
>   
> +/**
> + * drm_atomic_helper_colorop_create_state - Allocates and initializes colorop atomic state
> + * @colorop: drm colorop
> + *
> + * Initializes a pristine @drm_colorop_state.
> + *
> + * RETURNS:
> + * Pointer to new colorop state, or ERR_PTR on failure.
> + */
> +struct drm_colorop_state *
> +drm_atomic_helper_colorop_create_state(struct drm_colorop *colorop)
> +{
> +	struct drm_colorop_state *state;
> +
> +	state = kzalloc_obj(*state);
> +	if (!state)
> +		return ERR_PTR(-ENOMEM);
> +
> +	__drm_colorop_state_init(state, colorop);
> +
> +	return state;
> +}
> +
>   /**
>    * __drm_colorop_reset - reset state on colorop
>    * @colorop: drm colorop
>    * @colorop_state: colorop state to assign
>    *
> diff --git a/include/drm/drm_colorop.h b/include/drm/drm_colorop.h
> index bd082854ca74cac90b42020b09206a8516687666..874ed693329c0ecf94567c094744fe86fd08e382 100644
> --- a/include/drm/drm_colorop.h
> +++ b/include/drm/drm_colorop.h
> @@ -423,10 +423,12 @@ int drm_plane_colorop_3dlut_init(struct drm_device *dev, struct drm_colorop *col
>   				 struct drm_plane *plane, const struct drm_colorop_funcs *funcs,
>   				 uint32_t lut_size,
>   				 enum drm_colorop_lut3d_interpolation_type interpolation,
>   				 uint32_t flags);
>   
> +struct drm_colorop_state *
> +drm_atomic_helper_colorop_create_state(struct drm_colorop *colorop);
>   struct drm_colorop_state *
>   drm_atomic_helper_colorop_duplicate_state(struct drm_colorop *colorop);
>   
>   void drm_colorop_atomic_destroy_state(struct drm_colorop *colorop,
>   				      struct drm_colorop_state *state);
>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)