Re: [Intel-gfx] [PATCH v3 05/12] drm/edid: use struct detailed_timing member access in is_rb()

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Mar 28, 2022 at 05:34:26PM +0300, Jani Nikula wrote:
> Use struct detailed_timing member access instead of direct offsets to
> avoid casting.
> 
> Use BUILD_BUG_ON() for sanity check.
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/drm_edid.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 10da6b9b14fb..39c8bf4ca082 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2408,15 +2408,19 @@ drm_for_each_detailed_block(u8 *raw_edid, detailed_cb *cb, void *closure)
>  }
>  
>  static void
> -is_rb(struct detailed_timing *t, void *data)
> +is_rb(struct detailed_timing *descriptor, void *data)
>  {
> -	u8 *r = (u8 *)t;
> +	bool *res = data;
>  
> -	if (!is_display_descriptor(t, EDID_DETAIL_MONITOR_RANGE))
> +	if (!is_display_descriptor(descriptor, EDID_DETAIL_MONITOR_RANGE))
>  		return;
>  
> -	if (r[10] == DRM_EDID_CVT_SUPPORT_FLAG && r[15] & 0x10)
> -		*(bool *)data = true;
> +	BUILD_BUG_ON(offsetof(typeof(*descriptor), data.other_data.data.range.flags) != 10);
> +	BUILD_BUG_ON(offsetof(typeof(*descriptor), data.other_data.data.range.formula.cvt.flags) != 15);
> +
> +	if (descriptor->data.other_data.data.range.flags == DRM_EDID_CVT_SUPPORT_FLAG &&
> +	    descriptor->data.other_data.data.range.formula.cvt.flags & 0x10)
> +		*res = true;
>  }
>  
>  /* EDID 1.4 defines this explicitly.  For EDID 1.3, we guess, badly. */
> -- 
> 2.30.2

-- 
Ville Syrjälä
Intel