[PATCH] drm/vmwgfx: Re-introduce drm_crtc_helper_funcs::prepare

[Ian Forbes]

This function was removed in the referenced fixes commit and caused a
regression. This is because the presence of this function, even though it
is a noop, changes the behaviour of disable_outputs in
drm_atomic_helper.c:1211.

Fixes: 7b0062036c3b ("drm/vmwgfx: Implement virtual crc generation")
Signed-off-by: Ian Forbes <ian.for...@broadcom.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c 
b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
index 2041c4d48daa..37223f95cbec 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
@@ -409,6 +409,10 @@ static void vmw_stdu_crtc_mode_set_nofb(struct drm_crtc 
*crtc)
                          crtc->x, crtc->y);
 }
 
+static void vmw_stdu_crtc_helper_prepare(struct drm_crtc *crtc)
+{
+}
+
 static void vmw_stdu_crtc_atomic_disable(struct drm_crtc *crtc,
                                         struct drm_atomic_state *state)
 {
@@ -1463,6 +1467,7 @@ drm_plane_helper_funcs 
vmw_stdu_primary_plane_helper_funcs = {
 };
 
 static const struct drm_crtc_helper_funcs vmw_stdu_crtc_helper_funcs = {
+       .prepare = vmw_stdu_crtc_helper_prepare,
        .mode_set_nofb = vmw_stdu_crtc_mode_set_nofb,
        .atomic_check = vmw_du_crtc_atomic_check,
        .atomic_begin = vmw_du_crtc_atomic_begin,
-- 
2.34.1