This needs a fixes tag:

Fixes: 6eca310e8924 ("drm/nouveau/kms/nv50-: Add basic DPCD backlight support for nouveau")

with that fixed:

Reviewed-by: Lyude Paul lyude@redhat.com

On Tue, 2021-06-15 at 11:16 +0800, Chen Jiahao wrote:

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@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);