Hi Ville, Thank you for the patch! Yet something to improve: [auto build test ERROR on drm-intel/for-linux-next] [also build test ERROR on drm-tip/drm-tip next-20211015] [cannot apply to airlied/drm-next v5.15-rc5] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Ville-Syrjala/drm-i915-Move-PCH-modeset-code-into-its-own-file/20211015-151850 base: git://anongit.freedesktop.org/drm-intel for-linux-next config: x86_64-randconfig-a011-20211014 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project acb3b187c4c88650a6a717a1bcb234d27d0d7f54) 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 # https://github.com/0day-ci/linux/commit/7512167c38e587a77b2ea0f87e8c68fff112804e git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Ville-Syrjala/drm-i915-Move-PCH-modeset-code-into-its-own-file/20211015-151850 git checkout 7512167c38e587a77b2ea0f87e8c68fff112804e # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): >> drivers/gpu/drm/i915/display/intel_pch_display.c:437:6: error: no previous prototype for function 'lpt_disable_pch_transcoder' [-Werror,-Wmissing-prototypes] void lpt_disable_pch_transcoder(struct drm_i915_private *dev_priv) ^ drivers/gpu/drm/i915/display/intel_pch_display.c:437:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void lpt_disable_pch_transcoder(struct drm_i915_private *dev_priv) ^ static 1 error generated. vim +/lpt_disable_pch_transcoder +437 drivers/gpu/drm/i915/display/intel_pch_display.c da423910ea902380 Ville Syrjälä 2021-10-15 436 da423910ea902380 Ville Syrjälä 2021-10-15 @437 void lpt_disable_pch_transcoder(struct drm_i915_private *dev_priv) da423910ea902380 Ville Syrjälä 2021-10-15 438 { da423910ea902380 Ville Syrjälä 2021-10-15 439 u32 val; da423910ea902380 Ville Syrjälä 2021-10-15 440 da423910ea902380 Ville Syrjälä 2021-10-15 441 val = intel_de_read(dev_priv, LPT_TRANSCONF); da423910ea902380 Ville Syrjälä 2021-10-15 442 val &= ~TRANS_ENABLE; da423910ea902380 Ville Syrjälä 2021-10-15 443 intel_de_write(dev_priv, LPT_TRANSCONF, val); da423910ea902380 Ville Syrjälä 2021-10-15 444 /* wait for PCH transcoder off, transcoder state */ da423910ea902380 Ville Syrjälä 2021-10-15 445 if (intel_de_wait_for_clear(dev_priv, LPT_TRANSCONF, da423910ea902380 Ville Syrjälä 2021-10-15 446 TRANS_STATE_ENABLE, 50)) da423910ea902380 Ville Syrjälä 2021-10-15 447 drm_err(&dev_priv->drm, "Failed to disable PCH transcoder\n"); da423910ea902380 Ville Syrjälä 2021-10-15 448 da423910ea902380 Ville Syrjälä 2021-10-15 449 /* Workaround: clear timing override bit. */ da423910ea902380 Ville Syrjälä 2021-10-15 450 val = intel_de_read(dev_priv, TRANS_CHICKEN2(PIPE_A)); da423910ea902380 Ville Syrjälä 2021-10-15 451 val &= ~TRANS_CHICKEN2_TIMING_OVERRIDE; da423910ea902380 Ville Syrjälä 2021-10-15 452 intel_de_write(dev_priv, TRANS_CHICKEN2(PIPE_A), val); da423910ea902380 Ville Syrjälä 2021-10-15 453 } da423910ea902380 Ville Syrjälä 2021-10-15 454 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org