Hi Lyude,

FYI, the error/warning still remains.

tree:   https://github.com/intel/linux-intel-lts.git 5.10/preempt-rt
head:   92cafac7cc9c1af94b9b5b61e35fbbd39d4f5854
commit: ce5ae1651b65e1a62c2fd1c347a4a2473341bec7 [16339/17820] drm/nouveau/kms/nv50-: Add basic DPCD backlight support for nouveau
config: powerpc-randconfig-c003-20211021 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 3cea2505fd8d99a9ba0cb625aecfe28a47c4e3f8)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # https://github.com/intel/linux-intel-lts/commit/ce5ae1651b65e1a62c2fd1c347a4a2473341bec7
        git remote add intel-lts https://github.com/intel/linux-intel-lts.git
        git fetch --no-tags intel-lts 5.10/preempt-rt
        git checkout ce5ae1651b65e1a62c2fd1c347a4a2473341bec7
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash drivers/gpu/drm/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/gpu/drm/nouveau/dispnv50/disp.c:1390:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
           int ret;
               ^
   drivers/gpu/drm/nouveau/dispnv50/disp.c:1414:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
           int ret;
               ^
>> drivers/gpu/drm/nouveau/dispnv50/disp.c:1665:54: error: no member named 'backlight' in 'struct nouveau_connector'
           struct nouveau_backlight *backlight = nv_connector->backlight;
                                                 ~~~~~~~~~~~~  ^
>> drivers/gpu/drm/nouveau/dispnv50/disp.c:1670:28: error: incomplete definition of type 'struct nouveau_backlight'
           if (backlight && backlight->uses_dpcd) {
                            ~~~~~~~~~^
   drivers/gpu/drm/nouveau/dispnv50/disp.c:1665:9: note: forward declaration of 'struct nouveau_backlight'
           struct nouveau_backlight *backlight = nv_connector->backlight;
                  ^
   drivers/gpu/drm/nouveau/dispnv50/disp.c:1671:50: error: incomplete definition of type 'struct nouveau_backlight'
                   ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
                                                         ~~~~~~~~~^
   drivers/gpu/drm/nouveau/dispnv50/disp.c:1665:9: note: forward declaration of 'struct nouveau_backlight'
           struct nouveau_backlight *backlight = nv_connector->backlight;
                  ^
   drivers/gpu/drm/nouveau/dispnv50/disp.c:2661:1: warning: no previous prototype for function 'nv50_display_create' [-Wmissing-prototypes]
   nv50_display_create(struct drm_device *dev)
   ^
   drivers/gpu/drm/nouveau/dispnv50/disp.c:2660:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int
   ^
   static 
   3 warnings and 3 errors generated.


vim +1665 drivers/gpu/drm/nouveau/dispnv50/disp.c

  1652	
  1653	/* TODO: Should we extend this to PWM-only backlights?
  1654	 * As well, should we add a DRM helper for waiting for the backlight to acknowledge
  1655	 * the panel backlight has been shut off? Intel doesn't seem to do this, and uses a
  1656	 * fixed time delay from the vbios…
  1657	 */
  1658	static void
  1659	nv50_sor_atomic_disable(struct drm_encoder *encoder, struct drm_atomic_state *state)
  1660	{
  1661		struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
  1662		struct nouveau_drm *drm = nouveau_drm(nv_encoder->base.base.dev);
  1663		struct nouveau_crtc *nv_crtc = nouveau_crtc(nv_encoder->crtc);
  1664		struct nouveau_connector *nv_connector = nv50_outp_get_old_connector(state, nv_encoder);
> 1665		struct nouveau_backlight *backlight = nv_connector->backlight;
  1666		struct drm_dp_aux *aux = &nv_connector->aux;
  1667		int ret;
  1668		u8 pwr;
  1669	
> 1670		if (backlight && backlight->uses_dpcd) {
  1671			ret = drm_edp_backlight_disable(aux, &backlight->edp_info);
  1672			if (ret < 0)
  1673				NV_ERROR(drm, "Failed to disable backlight on [CONNECTOR:%d:%s]: %d\n",
  1674					 nv_connector->base.base.id, nv_connector->base.name, ret);
  1675		}
  1676	
  1677		if (nv_encoder->dcb->type == DCB_OUTPUT_DP) {
  1678			int ret = drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr);
  1679	
  1680			if (ret == 0) {
  1681				pwr &= ~DP_SET_POWER_MASK;
  1682				pwr |=  DP_SET_POWER_D3;
  1683				drm_dp_dpcd_writeb(aux, DP_SET_POWER, pwr);
  1684			}
  1685		}
  1686	
  1687		nv_encoder->update(nv_encoder, nv_crtc->index, NULL, 0, 0);
  1688		nv50_audio_disable(encoder, nv_crtc);
  1689		nv50_hdmi_disable(&nv_encoder->base.base, nv_crtc);
  1690		nv50_outp_release(nv_encoder);
  1691		nv_encoder->crtc = NULL;
  1692	}
  1693	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org