Re: [PATCH v3 1/6] drm: Add drm_mode_config->normalize_zpos boolean

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Jan 25, 2018 at 04:26:25PM +0200, Peter Ujfalusi wrote:
> Instead of drivers duplicating the drm_atomic_helper_check() code to be
> able to normalize the zpos they can use the normalize_zpos flag to let the
> drm core to do it.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 11 +++++++++++
>  include/drm/drm_mode_config.h       |  8 ++++++++
>  include/drm/drm_plane.h             |  4 ++--
>  3 files changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index ab4032167094..0f6a4949e6dc 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -873,6 +873,11 @@ EXPORT_SYMBOL(drm_atomic_helper_check_planes);
>   * functions depend upon an updated adjusted_mode.clock to e.g. properly compute
>   * watermarks.
>   *
> + * Note that zpos normalization will add all enable planes to the state which
> + * might not desired for some drivers.
> + * For example enable/disable of a cursor plane which have fixed zpos value
> + * would trigger all other enabled planes to be forced to the state change.
> + *
>   * RETURNS:
>   * Zero for success or -errno
>   */
> @@ -885,6 +890,12 @@ int drm_atomic_helper_check(struct drm_device *dev,
>  	if (ret)
>  		return ret;
>  
> +	if (dev->mode_config.normalize_zpos) {
> +		ret = drm_atomic_normalize_zpos(dev, state);
> +		if (ret)
> +			return ret;
> +	}

I think we originally had this in drm_atomic_helper_check_planes().
Looking through some of the drivers it looks like we could maybe
kill a few more LOC by putting it there.

> +
>  	ret = drm_atomic_helper_check_planes(dev, state);
>  	if (ret)
>  		return ret;
> diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
> index 2cb6f02df64a..987ab63ae037 100644
> --- a/include/drm/drm_mode_config.h
> +++ b/include/drm/drm_mode_config.h
> @@ -792,6 +792,14 @@ struct drm_mode_config {
>  	/* cursor size */
>  	uint32_t cursor_width, cursor_height;
>  
> +	/**
> +	 * @normalize_zpos:
> +	 *
> +	 * If true the drm core will call drm_atomic_normalize_zpos() as part of
> +	 * atomic mode checking from drm_atomic_helper_check()
> +	 */
> +	bool normalize_zpos;
> +

Can we pack it next to some other bools to try and keep the struct
size down?

>  	/**
>  	 * @suspend_state:
>  	 *
> diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
> index 8185e3468a23..2c0adb124e0f 100644
> --- a/include/drm/drm_plane.h
> +++ b/include/drm/drm_plane.h
> @@ -50,8 +50,8 @@ struct drm_modeset_acquire_ctx;
>   *	plane with a lower ID.
>   * @normalized_zpos: normalized value of zpos: unique, range from 0 to N-1
>   *	where N is the number of active planes for given crtc. Note that
> - *	the driver must call drm_atomic_normalize_zpos() to update this before
> - *	it can be trusted.
> + *	the driver must set drm_mode_config.normalize_zpos or call
> + *	drm_atomic_normalize_zpos() to update this before it can be trusted.
>   * @src: clipped source coordinates of the plane (in 16.16)
>   * @dst: clipped destination coordinates of the plane
>   * @state: backpointer to global drm_atomic_state
> -- 
> Peter
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

-- 
Ville Syrjälä
Intel OTC
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