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Date:   Fri, 17 Jun 2022 22:40:25 +0800
From:   kernel test robot <lkp@intel.com>
To:     Ricardo Ribalda <ribalda@chromium.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-kernel@vger.kernel.org, tfiga@chromium.org,
        senozhatsky@chromium.org, yunkec@google.com
Cc:     llvm@lists.linux.dev, kbuild-all@lists.01.org,
        linux-media@vger.kernel.org, Ricardo Ribalda <ribalda@chromium.org>
Subject: Re: [PATCH v7 2/8] media: uvcvideo: Add support for per-device
 control mapping overrides
Message-ID: <202206172239.M4dQBUhz-lkp@intel.com>
References: <20220617103645.71560-3-ribalda@chromium.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220617103645.71560-3-ribalda@chromium.org>
Precedence: bulk

Hi Ricardo,

I love your patch! Perhaps something to improve:

[auto build test WARNING on media-tree/master]
[also build test WARNING on linus/master v5.19-rc2 next-20220617]
[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/intel-lab-lkp/linux/commits/Ricardo-Ribalda/uvcvideo-Fix-handling-of-power_line_frequency/20220617-185644
base:   git://linuxtv.org/media_tree.git master
config: hexagon-randconfig-r045-20220617 (https://download.01.org/0day-ci/archive/20220617/202206172239.M4dQBUhz-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d764aa7fc6b9cc3fbe960019018f5f9e941eb0a6)
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/intel-lab-lkp/linux/commit/10bdca4191d7a8be97c77dbe4ba89c05713ee0e2
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Ricardo-Ribalda/uvcvideo-Fix-handling-of-power_line_frequency/20220617-185644
        git checkout 10bdca4191d7a8be97c77dbe4ba89c05713ee0e2
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/media/usb/uvc/

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

All warnings (new ones prefixed by >>):

>> drivers/media/usb/uvc/uvc_ctrl.c:2442:6: warning: variable 'mapping' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (chain->dev->info->mappings) {
               ^~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/media/usb/uvc/uvc_ctrl.c:2459:9: note: uninitialized use occurs here
           mend = mapping + ARRAY_SIZE(uvc_ctrl_mappings);
                  ^~~~~~~
   drivers/media/usb/uvc/uvc_ctrl.c:2442:2: note: remove the 'if' if its condition is always true
           if (chain->dev->info->mappings) {
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/media/usb/uvc/uvc_ctrl.c:2406:43: note: initialize the variable 'mapping' to silence this warning
           const struct uvc_control_mapping *mapping;
                                                    ^
                                                     = NULL
   1 warning generated.


vim +2442 drivers/media/usb/uvc/uvc_ctrl.c

  2396	
  2397	/*
  2398	 * Add control information and hardcoded stock control mappings to the given
  2399	 * device.
  2400	 */
  2401	static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
  2402				       struct uvc_control *ctrl)
  2403	{
  2404		const struct uvc_control_info *info = uvc_ctrls;
  2405		const struct uvc_control_info *iend = info + ARRAY_SIZE(uvc_ctrls);
  2406		const struct uvc_control_mapping *mapping;
  2407		const struct uvc_control_mapping *mend;
  2408	
  2409		/* XU controls initialization requires querying the device for control
  2410		 * information. As some buggy UVC devices will crash when queried
  2411		 * repeatedly in a tight loop, delay XU controls initialization until
  2412		 * first use.
  2413		 */
  2414		if (UVC_ENTITY_TYPE(ctrl->entity) == UVC_VC_EXTENSION_UNIT)
  2415			return;
  2416	
  2417		for (; info < iend; ++info) {
  2418			if (uvc_entity_match_guid(ctrl->entity, info->entity) &&
  2419			    ctrl->index == info->index) {
  2420				uvc_ctrl_add_info(chain->dev, ctrl, info);
  2421				/*
  2422				 * Retrieve control flags from the device. Ignore errors
  2423				 * and work with default flag values from the uvc_ctrl
  2424				 * array when the device doesn't properly implement
  2425				 * GET_INFO on standard controls.
  2426				 */
  2427				uvc_ctrl_get_flags(chain->dev, ctrl, &ctrl->info);
  2428				break;
  2429			 }
  2430		}
  2431	
  2432		if (!ctrl->initialized)
  2433			return;
  2434	
  2435		/*
  2436		 * First check if the device provides a custom mapping for this control,
  2437		 * used to override standard mappings for non-conformant devices. Don't
  2438		 * process standard mappings if a custom mapping is found. This
  2439		 * mechanism doesn't support combining standard and custom mappings for
  2440		 * a single control.
  2441		 */
> 2442		if (chain->dev->info->mappings) {
  2443			bool custom = false;
  2444			unsigned int i;
  2445	
  2446			for (i = 0; (mapping = chain->dev->info->mappings[i]); ++i) {
  2447				if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
  2448				    ctrl->info.selector == mapping->selector) {
  2449					__uvc_ctrl_add_mapping(chain, ctrl, mapping);
  2450					custom = true;
  2451				}
  2452			}
  2453	
  2454			if (custom)
  2455				return;
  2456		}
  2457	
  2458		/* Process common mappings next. */
  2459		mend = mapping + ARRAY_SIZE(uvc_ctrl_mappings);
  2460		for (mapping = uvc_ctrl_mappings; mapping < mend; ++mapping) {
  2461			if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
  2462			    ctrl->info.selector == mapping->selector)
  2463				__uvc_ctrl_add_mapping(chain, ctrl, mapping);
  2464		}
  2465	
  2466		/* Finally process version-specific mappings. */
  2467		if (chain->dev->uvc_version < 0x0150) {
  2468			mapping = uvc_ctrl_mappings_uvc11;
  2469			mend = mapping + ARRAY_SIZE(uvc_ctrl_mappings_uvc11);
  2470		} else {
  2471			mapping = uvc_ctrl_mappings_uvc15;
  2472			mend = mapping + ARRAY_SIZE(uvc_ctrl_mappings_uvc15);
  2473		}
  2474	
  2475		for (; mapping < mend; ++mapping) {
  2476			if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
  2477			    ctrl->info.selector == mapping->selector)
  2478				__uvc_ctrl_add_mapping(chain, ctrl, mapping);
  2479		}
  2480	}
  2481	

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