[PATCH v3] drm/tidss: dispc: Rewrite naive plane positioning code

[Tomi Valkeinen]

On 13/02/2020 12:44, Jyri Sarha wrote:

> +	/*
> +	 * If a plane on a CRTC changes add all active planes on that
> +	 * CRTC to the atomic state. This is needed for updating the
> +	 * plane positions in tidss_crtc_position_planes() which is
> +	 * called from crtc_atomic_enable() and crtc_atomic_flush().
> +	 * The update is needed for x,y-position changes too, so
> +	 * zpos_changed condition is not enough and we need this if
> +	 * planes_changed is true too.
> +	 */
> +	for_each_new_crtc_in_state(state, crtc, cstate, i) {
> +		if (cstate->zpos_changed || cstate->planes_changed) {
> +			ret = drm_atomic_add_affected_planes(state, crtc);
> +			if (ret)
> +				return ret;
> +		}
> +	}

I think 99.99...% of the commits are such where only planes' fb address is changed. I think 
"planes_changed" is true for these. I wonder if it would be a sensible optimization to skip this for 
those 99.99...% cases. Can we detect that easily?

Well, we haven't optimized for those 99.99...% cases anywhere else either, so it's possible it 
doesn't matter.

  Tomi

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