[PATCH] drm: nouveau: fix nouveau_backlight compiling error

[Chen Jiahao]

There is a compiling error in disp.c while not selecting
CONFIG_DRM_NOUVEAU_BACKLIGHT:

drivers/gpu/drm/nouveau/dispnv50/disp.c: In function ‘nv50_sor_atomic_disable’:
drivers/gpu/drm/nouveau/dispnv50/disp.c:1665:52: error:
‘struct nouveau_connector’ has no member named ‘backlight’
 1665 |  struct nouveau_backlight *backlight = nv_connector->backlight;
      |                                                    ^~
drivers/gpu/drm/nouveau/dispnv50/disp.c:1670:28: error: dereferencing pointer
to incomplete type ‘struct nouveau_backlight’
 1670 |  if (backlight && backlight->uses_dpcd) {
      |                            ^~

The problem is solved by adding the CONFIG_DRM_NOUVEAU_BACKLIGHT dependency
where struct nouveau_backlight is used.

Signed-off-by: Chen Jiahao <chenjiahao16 at huawei.com>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 093e1f7163b3..d266b7721e29 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1662,17 +1662,21 @@ nv50_sor_atomic_disable(struct drm_encoder *encoder, struct drm_atomic_state *st
 	struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(nv_encoder->crtc);
 	struct nouveau_connector *nv_connector = nv50_outp_get_old_connector(state, nv_encoder);
+#ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT
 	struct nouveau_backlight *backlight = nv_connector->backlight;
+#endif
 	struct drm_dp_aux *aux = &nv_connector->aux;
 	int ret;
 	u8 pwr;
 
+#ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT
 	if (backlight && backlight->uses_dpcd) {
 		ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
 		if (ret < 0)
 			NV_ERROR(drm, "Failed to disable backlight on [CONNECTOR:%d:%s]: %d\n",
 				 nv_connector->base.base.id, nv_connector->base.name, ret);
 	}
+#endif
 
 	if (nv_encoder->dcb->type == DCB_OUTPUT_DP) {
 		int ret = drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr);
-- 
2.31.1