Hi Sean, I love your patch! Perhaps something to improve: [auto build test WARNING on drm-tip/drm-tip] [also build test WARNING on drm-exynos/exynos-drm-next tegra-drm/drm/tegra/for-next linus/master v5.15-rc1 next-20210914] [cannot apply to drm-intel/for-linux-next drm/drm-next] [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/Sean-Paul/drm-hdcp-Pull-HDCP-aut... base: git://anongit.freedesktop.org/drm/drm-tip drm-tip config: riscv-randconfig-r042-20210913 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 261cbe98c38f8c1ee1a482fe76511110e790f58a) 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 riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://github.com/0day-ci/linux/commit/ceee3075ca23d7911b80eb6a71a0b352d... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Sean-Paul/drm-hdcp-Pull-HDCP-auth-exchange-check-into/20210914-020004 git checkout ceee3075ca23d7911b80eb6a71a0b352d7c6b52c # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 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/drm_hdcp.c:13: In file included from include/linux/i2c.h:18: In file included from include/linux/regulator/consumer.h:35: In file included from include/linux/suspend.h:5: In file included from include/linux/swap.h:9: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/riscv/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/riscv/include/asm/io.h:136: include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from drivers/gpu/drm/drm_hdcp.c:13: In file included from include/linux/i2c.h:18: In file included from include/linux/regulator/consumer.h:35: In file included from include/linux/suspend.h:5: In file included from include/linux/swap.h:9: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/riscv/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/riscv/include/asm/io.h:136: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from drivers/gpu/drm/drm_hdcp.c:13: In file included from include/linux/i2c.h:18: In file included from include/linux/regulator/consumer.h:35: In file included from include/linux/suspend.h:5: In file included from include/linux/swap.h:9: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/riscv/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/riscv/include/asm/io.h:136: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:1024:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port; ~~~~~~~~~~ ^ bool type_changed, needs_enable; ^ 8 warnings generated. vim +/needs_enable +1280 drivers/gpu/drm/drm_hdcp.c 1251 1252 /** 1253 * drm_hdcp_helper_atomic_commit - Helper for drivers to call during commit to 1254 * enable/disable HDCP 1255 * 1256 * @data: pointer to the @drm_hdcp_helper_data for the connector 1257 * @state: pointer to the atomic state being committed 1258 * @driver_mutex: driver-provided lock to be used while interacting with the driver 1259 * 1260 * This function can be used by display drivers to determine when HDCP should be 1261 * enabled or disabled based on the connector state. It should be called during 1262 * steady-state commits as well as connector enable/disable. The function will 1263 * handle the HDCP authentication/encryption logic, calling back into the driver 1264 * when source operations are necessary. 1265 * 1266 * @driver_mutex will be retained and used for the duration of the HDCP session 1267 * since it will be needed for link checks and retries. This mutex is useful if 1268 * the driver has shared resources across connectors which must be serialized. 1269 * For example, driver_mutex can be used for MST connectors sharing a common 1270 * encoder which should not be accessed/changed concurrently. When the 1271 * connector's session is torn down, the mutex will be forgotten by the helper 1272 * for this connector until the next session. 1273 */ 1274 void drm_hdcp_helper_atomic_commit(struct drm_hdcp_helper_data *data, 1275 struct drm_atomic_state *state, 1276 struct mutex *driver_mutex) 1277 { 1278 struct drm_connector *connector = data->connector; 1279 struct drm_connector_state *conn_state; 1281 1282 conn_state = drm_atomic_get_new_connector_state(state, connector); 1283 1284 type_changed = conn_state->hdcp_content_type != data->enabled_type; 1285 needs_enable = type_changed; 1286 1287 if (conn_state->content_protection == DRM_MODE_CONTENT_PROTECTION_UNDESIRED) { 1288 drm_hdcp_helper_disable_hdcp(data); 1289 return; 1290 } 1291 1292 if (!conn_state->crtc) { 1293 drm_hdcp_helper_disable_hdcp(data); 1294 1295 /* Restore property to DESIRED so it's retried later */ 1296 if (conn_state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED) { 1297 mutex_lock(&data->mutex); 1298 drm_hdcp_update_value(data, DRM_MODE_CONTENT_PROTECTION_DESIRED, 1299 true); 1300 mutex_unlock(&data->mutex); 1301 } 1302 return; 1303 } 1304 1305 /* Already enabled */ 1306 if (conn_state->content_protection == DRM_MODE_CONTENT_PROTECTION_ENABLED) 1307 return; 1308 1309 /* Disable and re-enable HDCP on content type change */ 1310 if (type_changed) 1311 drm_hdcp_helper_disable_hdcp(data); 1312 1313 drm_hdcp_helper_enable_hdcp(data, state, driver_mutex); 1314 } 1315 EXPORT_SYMBOL(drm_hdcp_helper_atomic_commit); 1316 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org