sound/usb/mixer_scarlett_gen2.c:2429:3: warning: Value stored to 'err' is never read [clang-analyzer-deadcode.DeadStores]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f
commit: d5bda7e03982f67ce2f6c0d79b750fb27077331a ALSA: usb-audio: scarlett2: Add support for the talkback feature
date:   3 months ago
:::::: branch date: 11 hours ago
:::::: commit date: 3 months ago
config: i386-randconfig-c001-20210910 (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
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d5bda7e03982f67ce2f6c0d79b750fb27077331a
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout d5bda7e03982f67ce2f6c0d79b750fb27077331a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=i386 clang-analyzer

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>


clang-analyzer warnings: (new ones prefixed by >>)

quoted

sound/usb/mixer_scarlett_gen2.c:2429:3: warning: Value stored to 'err' is never read [clang-analyzer-deadcode.DeadStores]

                   err = scarlett2_usb_get_config(mixer,
                   ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/err +2429 sound/usb/mixer_scarlett_gen2.c

6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2369
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2370  static int scarlett2_update_monitor_other(struct usb_mixer_interface *mixer)
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2371  {
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2372  	struct scarlett2_data *private = mixer->private_data;
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2373  	const struct scarlett2_device_info *info = private->info;
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2374  	int err;
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2375
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2376  	/* monitor_other_enable[0] enables speaker switching
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2377  	 * monitor_other_enable[1] enables talkback
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2378  	 */
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2379  	u8 monitor_other_enable[2];
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2380
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2381  	/* monitor_other_switch[0] activates the alternate speakers
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2382  	 * monitor_other_switch[1] activates talkback
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2383  	 */
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2384  	u8 monitor_other_switch[2];
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2385
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2386  	private->monitor_other_updated = 0;
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2387
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2388  	if (info->direct_monitor)
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2389  		return scarlett2_usb_get_config(
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2390  			mixer, SCARLETT2_CONFIG_DIRECT_MONITOR,
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2391  			1, &private->direct_monitor_switch);
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2392
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2393  	/* if it doesn't do speaker switching then it also doesn't do
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2394  	 * talkback
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2395  	 */
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2396  	if (!info->has_speaker_switching)
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2397  		return 0;
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2398
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2399  	err = scarlett2_usb_get_config(
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2400  		mixer, SCARLETT2_CONFIG_MONITOR_OTHER_ENABLE,
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2401  		2, monitor_other_enable);
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2402  	if (err < 0)
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2403  		return err;
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2404
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2405  	err = scarlett2_usb_get_config(
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2406  		mixer, SCARLETT2_CONFIG_MONITOR_OTHER_SWITCH,
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2407  		2, monitor_other_switch);
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2408  	if (err < 0)
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2409  		return err;
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2410
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2411  	if (!monitor_other_enable[0])
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2412  		private->speaker_switching_switch = 0;
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2413  	else
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2414  		private->speaker_switching_switch = monitor_other_switch[0] + 1;
e914d8432cb4b9 Geoffrey D. Bennett 2021-06-23  2415
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2416  	if (info->has_talkback) {
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2417  		const int (*port_count)[SCARLETT2_PORT_DIRNS] =
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2418  			info->port_count;
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2419  		int num_mixes =
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2420  			port_count[SCARLETT2_PORT_TYPE_MIX][SCARLETT2_PORT_IN];
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2421  		u16 bitmap;
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2422  		int i;
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2423
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2424  		if (!monitor_other_enable[1])
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2425  			private->talkback_switch = 0;
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2426  		else
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2427  			private->talkback_switch = monitor_other_switch[1] + 1;
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2428
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23 @2429  		err = scarlett2_usb_get_config(mixer,
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2430  					       SCARLETT2_CONFIG_TALKBACK_MAP,
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2431  					       1, &bitmap);
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2432  		for (i = 0; i < num_mixes; i++, bitmap >>= 1)
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2433  			private->talkback_map[i] = bitmap & 1;
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2434  	}
d5bda7e03982f6 Geoffrey D. Bennett 2021-06-23  2435
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2436  	return 0;
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2437  }
6ef9fa4a0eb4cd Geoffrey D. Bennett 2021-06-23  2438

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