Re: [PATCH v2 4/5] drm: Add and export function drm_gem_cma_sync_data

Christoph Hellwig
2021-03-11T12:30:34Z

On Sun, Mar 07, 2021 at 08:28:34PM +0000, Paul Cercueil wrote:
> + drm_atomic_for_each_plane_damage(&iter, &clip) {
> + for (i = 0; i < finfo->num_planes; i++) {
> + daddr = drm_fb_cma_get_gem_addr(state->fb, state, i);
> +
> + /* Ignore x1/x2 values, invalidate complete lines */
> + offset = clip.y1 * state->fb->pitches[i];
> +
> + dma_sync_single_for_device(dev, daddr + offset,
> + (clip.y2 - clip.y1) * state->fb->pitches[i],
> + DMA_TO_DEVICE);

Are these helpers only ever used to transfer data to the device and
never from it? If so please clearly document that.