drm/atomic-helper: Add {begin,end}_fb_access to plane helpers

Add {begin,end}_fb_access helpers to run at the beginning and end of
an atomic commit. The begin_fb_access helper acquires resources that
are necessary to perform the atomic commit. It it similar to prepare_fb,
except that the resources are to be released at the end of the commit.
Resources acquired by prepare_fb are held until after the next pageflip.

The end_fb_access helper performs the corresponding resource cleanup.
Atomic helpers call it with the new plane state. This is different from
cleanup_fb, which releases resources of the old plane state.

v2:
	* fix typos in commit message (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221025101737.8874-2-tzimmermann@suse.de

1 files changed, 20 insertions, 0 deletions

diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
index 0b3647e614dd..2298fe3af4cd 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -136,6 +136,26 @@ struct drm_simple_display_pipe_funcs {
 			   struct drm_plane_state *plane_state);
 
 	/**
+	 * @begin_fb_access:
+	 *
+	 * Optional, called by &drm_plane_helper_funcs.begin_fb_access. Please read
+	 * the documentation for the &drm_plane_helper_funcs.begin_fb_access hook for
+	 * more details.
+	 */
+	int (*begin_fb_access)(struct drm_simple_display_pipe *pipe,
+			       struct drm_plane_state *new_plane_state);
+
+	/**
+	 * @end_fb_access:
+	 *
+	 * Optional, called by &drm_plane_helper_funcs.end_fb_access. Please read
+	 * the documentation for the &drm_plane_helper_funcs.end_fb_access hook for
+	 * more details.
+	 */
+	void (*end_fb_access)(struct drm_simple_display_pipe *pipe,
+			      struct drm_plane_state *plane_state);
+
+	/**
 	 * @enable_vblank:
 	 *
 	 * Optional, called by &drm_crtc_funcs.enable_vblank. Please read