Re: drivers/hid/hid-nvidia-shield.c:59:2: warning: field within 'struct thunderstrike_hostcmd_resp_report' is less aligned than 'union thunderstrike_hostcmd_resp_report::(anonymous at drivers/hid/hid-nvidia-shield.c:59:2)' and is usually due to 'struct thund...

[Rahul Rameshbabu]

On Tue, 04 Jul, 2023 15:13:08 +0800 kernel test robot <lkp@xxxxxxxxx> wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   24be4d0b46bb0c3c1dc7bacd30957d6144a70dfc
> commit: 09308562d4afb1abc66366608fa1cb9de783272f HID: nvidia-shield: Initial driver implementation with Thunderstrike support
> date:   4 weeks ago
> config: arm-randconfig-r014-20230704 (https://download.01.org/0day-ci/archive/20230704/202307041500.6bKn7nCl-lkp@xxxxxxxxx/config)
> compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git f28c006a5895fc0e329fe15fead81e37457cb1d1)
> reproduce: (https://download.01.org/0day-ci/archive/20230704/202307041500.6bKn7nCl-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202307041500.6bKn7nCl-lkp@xxxxxxxxx/
>
> All warnings (new ones prefixed by >>):
>
>>> drivers/hid/hid-nvidia-shield.c:59:2: warning: field  within 'struct thunderstrike_hostcmd_resp_report' is less aligned than 'union thunderstrike_hostcmd_resp_report::(anonymous at drivers/hid/hid-nvidia-shield.c:59:2)' and is usually due to 'struct thunderstrike_hostcmd_resp_report' being packed, which can lead to unaligned accesses [-Wunaligned-access]
>            union {
>            ^
>    1 warning generated.
>
>
> vim +59 drivers/hid/hid-nvidia-shield.c
>
>     53	
>     54	struct thunderstrike_hostcmd_resp_report {
>     55		u8 report_id; /* THUNDERSTRIKE_HOSTCMD_RESP_REPORT_ID */
>     56		u8 cmd_id;
>     57		u8 reserved_at_10;
>     58	
>   > 59		union {
>     60			struct thunderstrike_hostcmd_board_info board_info;
>     61			struct thunderstrike_hostcmd_haptics motors;
>     62			__le16 fw_version;
>     63			u8 payload[30];
>     64		};
>     65	} __packed;
>     66	static_assert(sizeof(struct thunderstrike_hostcmd_resp_report) ==
>     67		      THUNDERSTRIKE_HOSTCMD_REPORT_SIZE);
>     68	

Will send out a fix for this soon.

-- Rahul Rameshbabu