From d81e9ee9f808610bc3c37f201d261a70c2861b7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Thu, 4 Nov 2021 15:18:46 +0100
Subject: drm/atomic-helper: support more than one write fence in
 drm_gem_plane_helper_prepare_fb
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: c382df714a8433dfdd4b84fecc00dc46fc755eb7
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Use dma_resv_get_singleton() here to eventually get more than one write
fence as single fence.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-13-christian.koenig@amd.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/drm_gem_atomic_helper.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
index c3189afe10cb..9338ddb7edff 100644
--- a/drivers/gpu/drm/drm_gem_atomic_helper.c
+++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
@@ -143,25 +143,21 @@
  */
 int drm_gem_plane_helper_prepare_fb(struct drm_plane *plane, struct drm_plane_state *state)
 {
-	struct dma_resv_iter cursor;
 	struct drm_gem_object *obj;
 	struct dma_fence *fence;
+	int ret;
 
 	if (!state->fb)
 		return 0;
 
 	obj = drm_gem_fb_get_obj(state->fb, 0);
-	dma_resv_iter_begin(&cursor, obj->resv, false);
-	dma_resv_for_each_fence_unlocked(&cursor, fence) {
-		/* TODO: Currently there should be only one write fence, so this
-		 * here works fine. But drm_atomic_set_fence_for_plane() should
-		 * be changed to be able to handle more fences in general for
-		 * multiple BOs per fb anyway. */
-		dma_fence_get(fence);
-		break;
-	}
-	dma_resv_iter_end(&cursor);
+	ret = dma_resv_get_singleton(obj->resv, false, &fence);
+	if (ret)
+		return ret;
 
+	/* TODO: drm_atomic_set_fence_for_plane() should be changed to be able
+	 * to handle more fences in general for multiple BOs per fb.
+	 */
 	drm_atomic_set_fence_for_plane(state, fence);
 	return 0;
 }
-- 
2.38.1