Re: Build failure with GCC 15 in drivers/gpu/drm/display/drm_dp_dual_mode_helper.c

On Tue, Oct 01, 2024 at 07:18:23PM +0530, Brahmajit wrote:
> On 01.10.2024 16:28, Ville Syrjälä wrote:
> > Looks like gcc is warning about perfectly legal code
> > (as far as the C standard goes).
> > 
> > But we could work around by adding room for the '\0' and
> > s/sizeof(...)/DP_DUAL_MODE_HDMI_ID_LEN/ in the memcmp().
> 
> Sorry I'm new, but can we do something like this?
> 
> --- a/drivers/gpu/drm/display/drm_dp_dual_mode_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_dual_mode_helper.c
> @@ -158,13 +158,13 @@ ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter,
>  }
>  EXPORT_SYMBOL(drm_dp_dual_mode_write);
>  
> -static bool is_hdmi_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN])
> +static bool is_hdmi_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN+1])

This should not have the +1

>  {
> -	static const char dp_dual_mode_hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] =
> +	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+1) == 0;

and neither should this

>  }
>  
>  static bool is_type1_adaptor(uint8_t adaptor_id)
> 
> -- 
> Regards,
> Brahmajit

-- 
Ville Syrjälä
Intel