Hi Thomas, I love your patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v5.10-rc3] [cannot apply to next-20201113] [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/Thomas-Zimmermann/drm-Build-fixe... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git f8394f232b1eab649ce2df5c5f15b0e528c92091 config: arm64-randconfig-r006-20201113 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 9a85643cd357e412cff69067bb5c4840e228c2ab) 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 arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # https://github.com/0day-ci/linux/commit/1e81f225d3ffc9e951faab8deb96ef620... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Thomas-Zimmermann/drm-Build-fixes-for-msm-and-mediatek/20201109-183736 git checkout 1e81f225d3ffc9e951faab8deb96ef6209db7742 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): In file included from drivers/gpu/drm/mediatek/mtk_drm_crtc.c:23: int mtk_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map); ^ drivers/gpu/drm/mediatek/mtk_drm_gem.h:49:66: warning: declaration of 'struct dma_buf_map' will not be visible outside of this function [-Wvisibility] void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map); ^ 2 warnings generated. -- In file included from drivers/gpu/drm/mediatek/mtk_drm_drv.c:32: int mtk_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map); ^ drivers/gpu/drm/mediatek/mtk_drm_gem.h:49:66: warning: declaration of 'struct dma_buf_map' will not be visible outside of this function [-Wvisibility] void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map); ^ drivers/gpu/drm/mediatek/mtk_drm_drv.c:316:24: warning: no previous prototype for function 'mtk_drm_gem_prime_import' [-Wmissing-prototypes] struct drm_gem_object *mtk_drm_gem_prime_import(struct drm_device *dev, ^ drivers/gpu/drm/mediatek/mtk_drm_drv.c:316:1: note: declare 'static' if the function is not intended to be used outside of this translation unit struct drm_gem_object *mtk_drm_gem_prime_import(struct drm_device *dev, ^ static drivers/gpu/drm/mediatek/mtk_drm_drv.c:337:20: error: incompatible function pointer types initializing 'void *(*)(struct drm_gem_object *)' with an expression of type 'int (struct drm_gem_object *, struct dma_buf_map *)' [-Werror,-Wincompatible-function-pointer-types] .gem_prime_vmap = mtk_drm_gem_prime_vmap, ^~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/mediatek/mtk_drm_drv.c:338:22: error: incompatible function pointer types initializing 'void (*)(struct drm_gem_object *, void *)' with an expression of type 'void (struct drm_gem_object *, struct dma_buf_map *)' [-Werror,-Wincompatible-function-pointer-types] .gem_prime_vunmap = mtk_drm_gem_prime_vunmap, ^~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/mediatek/mtk_drm_drv.c:500:15: warning: cast to smaller integer type 'enum mtk_ddp_comp_type' from 'const void *' [-Wvoid-pointer-to-enum-cast] comp_type = (enum mtk_ddp_comp_type)of_id->data; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4 warnings and 2 errors generated. -- In file included from drivers/gpu/drm/mediatek/mtk_drm_gem.c:14: int mtk_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map); ^ drivers/gpu/drm/mediatek/mtk_drm_gem.h:49:66: warning: declaration of 'struct dma_buf_map' will not be visible outside of this function [-Wvisibility] void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map); ^ drivers/gpu/drm/mediatek/mtk_drm_gem.c:232:63: warning: declaration of 'struct dma_buf_map' will not be visible outside of this function [-Wvisibility] int mtk_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map) ^ drivers/gpu/drm/mediatek/mtk_drm_gem.c:232:5: error: conflicting types for 'mtk_drm_gem_prime_vmap' int mtk_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map) ^ drivers/gpu/drm/mediatek/mtk_drm_gem.h:48:5: note: previous declaration is here int mtk_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map); ^ drivers/gpu/drm/mediatek/mtk_drm_gem.c:259:2: error: implicit declaration of function 'dma_buf_map_set_vaddr' [-Werror,-Wimplicit-function-declaration] dma_buf_map_set_vaddr(map, mtk_gem->kvaddr); ^ drivers/gpu/drm/mediatek/mtk_drm_gem.c:264:66: warning: declaration of 'struct dma_buf_map' will not be visible outside of this function [-Wvisibility] void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map) ^ drivers/gpu/drm/mediatek/mtk_drm_gem.c:264:6: error: conflicting types for 'mtk_drm_gem_prime_vunmap' void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map) ^ drivers/gpu/drm/mediatek/mtk_drm_gem.h:49:6: note: previous declaration is here void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map); ^ drivers/gpu/drm/mediatek/mtk_drm_gem.c:267:19: error: incomplete definition of type 'struct dma_buf_map' void *vaddr = map->vaddr; ~~~^ drivers/gpu/drm/mediatek/mtk_drm_gem.c:264:66: note: forward declaration of 'struct dma_buf_map' void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map) ^ 4 warnings and 4 errors generated. vim +48 drivers/gpu/drm/mediatek/mtk_drm_gem.h 36 37 void mtk_drm_gem_free_object(struct drm_gem_object *gem); 38 struct mtk_drm_gem_obj *mtk_drm_gem_create(struct drm_device *dev, size_t size, 39 bool alloc_kmap); 40 int mtk_drm_gem_dumb_create(struct drm_file *file_priv, struct drm_device *dev, 41 struct drm_mode_create_dumb *args); 42 int mtk_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma); 43 int mtk_drm_gem_mmap_buf(struct drm_gem_object *obj, 44 struct vm_area_struct *vma); 45 struct sg_table *mtk_gem_prime_get_sg_table(struct drm_gem_object *obj); 46 struct drm_gem_object *mtk_gem_prime_import_sg_table(struct drm_device *dev, 47 struct dma_buf_attachment *attach, struct sg_table *sg); 49 void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map); 50 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org