Synchronize CPU access to GEM BOs with other drivers when updating the
screen buffer. Imported buffers might otherwise contain stale data.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/tiny/simpledrm.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 5f242558891e..18489779fb8a 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -480,11 +480,15 @@ static void simpledrm_primary_plane_helper_atomic_update(struct drm_plane *plane
struct simpledrm_device *sdev = simpledrm_device_of_dev(dev);
struct drm_atomic_helper_damage_iter iter;
struct drm_rect damage;
- int idx;
+ int ret, idx;
- if (!drm_dev_enter(dev, &idx))
+ ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
+ if (ret)
return;
+ if (!drm_dev_enter(dev, &idx))
+ goto out_drm_gem_fb_end_cpu_access;
+
drm_atomic_helper_damage_iter_init(&iter, old_plane_state, plane_state);
drm_atomic_for_each_plane_damage(&iter, &damage) {
struct iosys_map dst = IOSYS_MAP_INIT_VADDR(sdev->screen_base);
@@ -499,6 +503,8 @@ static void simpledrm_primary_plane_helper_atomic_update(struct drm_plane *plane
}
drm_dev_exit(idx);
+out_drm_gem_fb_end_cpu_access:
+ drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
}
static void simpledrm_primary_plane_helper_atomic_disable(struct drm_plane *plane,
--
2.37.3
