Re: [Intel-gfx] [PATCH 05/12] drm/edid: pass struct edid to connector_bad_edid()

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

On Thu, Apr 07, 2022 at 12:14:31PM +0300, Jani Nikula wrote:
> Avoid casting here and there, and make it const.
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c | 15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 8638e54e0879..ba54701f91f6 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -1967,7 +1967,7 @@ drm_do_probe_ddc_edid(void *data, u8 *buf, unsigned int block, size_t len)
>  }
>  
>  static void connector_bad_edid(struct drm_connector *connector,
> -			       u8 *edid, int num_blocks)
> +			       const struct edid *edid, int num_blocks)
>  {
>  	int i;
>  	u8 last_block;
> @@ -1978,22 +1978,19 @@ static void connector_bad_edid(struct drm_connector *connector,
>  	 * of 0x7e in the EDID of the _index_ of the last block in the
>  	 * combined chunk of memory.
>  	 */
> -	last_block = edid[0x7e];
> +	last_block = edid->extensions;
>  
>  	/* Calculate real checksum for the last edid extension block data */
>  	if (last_block < num_blocks)
>  		connector->real_edid_checksum =
> -			edid_block_compute_checksum(edid + last_block * EDID_LENGTH);
> +			edid_block_compute_checksum(edid + last_block);
>  
>  	if (connector->bad_edid_counter++ && !drm_debug_enabled(DRM_UT_KMS))
>  		return;
>  
>  	drm_dbg_kms(connector->dev, "%s: EDID is invalid:\n", connector->name);
> -	for (i = 0; i < num_blocks; i++) {
> -		u8 *block = edid + i * EDID_LENGTH;
> -
> -		edid_block_dump(KERN_DEBUG, block, i);
> -	}
> +	for (i = 0; i < num_blocks; i++)
> +		edid_block_dump(KERN_DEBUG, edid + i, i);

nit: I'm not a big fan of pointer arithmetic in general. IMO it
makes it a bit too easy to miss the fact that it's not counting
bytes but rather potentially something much bigger. So I tend to
prefer array notation for such things. But looks like most of 
these go away at the end anyway with the block_data() stuff.

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

>  }
>  
>  /* Get override or firmware EDID */
> @@ -2139,7 +2136,7 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
>  	}
>  
>  	if (invalid_blocks) {
> -		connector_bad_edid(connector, (u8 *)edid, edid->extensions + 1);
> +		connector_bad_edid(connector, edid, edid->extensions + 1);
>  
>  		edid = edid_filter_invalid_blocks(edid, invalid_blocks);
>  	}
> -- 
> 2.30.2

-- 
Ville Syrjälä
Intel