[PATCH 1/1] drm/display: Fix building with GCC 15

[Jani Nikula]

On Tue, 01 Oct 2024, Brahmajit Das <brahmajit.xyz at gmail.com> wrote:
> GCC 15 enables -Werror=unterminated-string-initialization by default.
> This results in the following build error
>
> drivers/gpu/drm/display/drm_dp_dual_mode_helper.c: In function ‘is_hdmi_adaptor’:
> drivers/gpu/drm/display/drm_dp_dual_mode_helper.c:164:17: error: initializer-string for array of
>  ‘char’ is too long [-Werror=unterminated-string-initialization]
>   164 |                 "DP-HDMI ADAPTOR\x04";
>       |                 ^~~~~~~~~~~~~~~~~~~~~
>
> After discussion with Ville, the fix was to increase the size of
> dp_dual_mode_hdmi_id array by one, so that it can accommodate the new
> line character. This should let us build the kernel with GCC 15.

Should be terminating NUL, not new line.

>
> Signed-off-by: Brahmajit Das <brahmajit.xyz at gmail.com>
> ---
>  drivers/gpu/drm/display/drm_dp_dual_mode_helper.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/display/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/display/drm_dp_dual_mode_helper.c
> index 14a2a8473682..295375868db6 100644
> --- a/drivers/gpu/drm/display/drm_dp_dual_mode_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_dual_mode_helper.c
> @@ -160,11 +160,12 @@ EXPORT_SYMBOL(drm_dp_dual_mode_write);
>  
>  static bool is_hdmi_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN])
>  {
> -	static const char dp_dual_mode_hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] =
> +	//+1 to avaoid spurious -Werror=unterminated-string-initialization warning

If we added comments for every little thing like this, there'd be more
comments than code. ;)

> +	static const char dp_dual_mode_hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN + 1] =
>  		"DP-HDMI ADAPTOR\x04";
>  
>  	return memcmp(hdmi_id, dp_dual_mode_hdmi_id,
> -		      sizeof(dp_dual_mode_hdmi_id)) == 0;
> +		      DP_DUAL_MODE_HDMI_ID_LEN) == 0;
>  }
>  
>  static bool is_type1_adaptor(uint8_t adaptor_id)

-- 
Jani Nikula, Intel