tree:   https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git master
head:   6eefec4a0b668de9bbb33bd3e7acfbcc794162b0
commit: 0b10c8c84c0c78ba4456bdbeb8a5b6ee58f47e39 [11/13] Bluetooth: btusb: Record debug log for Mediatek Chip.
config: arc-allyesconfig (attached as .config)
compiler: arceb-elf-gcc (GCC) 10.3.0
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/bluetooth/bluetooth-next.git/commit/?id=0b10c8c84c0c78ba4456bdbeb8a5b6ee58f47e39
        git remote add bluetooth-next https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git
        git fetch --no-tags bluetooth-next master
        git checkout 0b10c8c84c0c78ba4456bdbeb8a5b6ee58f47e39
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=arc 

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

All warnings (new ones prefixed by >>):

   drivers/bluetooth/btusb.c: In function 'btusb_recv_acl_mtk':
>> drivers/bluetooth/btusb.c:3901:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
    3901 |   usb_disable_autosuspend(data->udev);
         |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/bluetooth/btusb.c:3902:2: note: here
    3902 |  case 0x05ff:  /* Firmware debug logging 1 */
         |  ^~~~


vim +3901 drivers/bluetooth/btusb.c

  3890	
  3891	static int btusb_recv_acl_mtk(struct hci_dev *hdev, struct sk_buff *skb)
  3892	{
  3893		struct btusb_data *data = hci_get_drvdata(hdev);
  3894		u16 handle = le16_to_cpu(hci_acl_hdr(skb)->handle);
  3895	
  3896		switch (handle) {
  3897		case 0xfc6f:		/* Firmware dump from device */
  3898			/* When the firmware hangs, the device can no longer
  3899			 * suspend and thus disable auto-suspend.
  3900			 */
> 3901			usb_disable_autosuspend(data->udev);
  3902		case 0x05ff:		/* Firmware debug logging 1 */
  3903		case 0x05fe:		/* Firmware debug logging 2 */
  3904			return hci_recv_diag(hdev, skb);
  3905		}
  3906	
  3907		return hci_recv_frame(hdev, skb);
  3908	}
  3909	

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