Re: [REBASE 7/7] drm/edid: make drm_edid_are_equal() more convenient for its single user

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Hi

Am 16.04.24 um 11:20 schrieb Jani Nikula:
> Repurpose drm_edid_are_equal() to be more helpful for its single user,
> and rename drm_edid_eq(). Functionally deduce the length from the blob
> size, not the blob data, making it more robust against any errors.

Could be squashed into patch 6.

Best regards
Thomas

> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
>   drivers/gpu/drm/drm_edid.c | 41 ++++++++++++++------------------------
>   1 file changed, 15 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 463fbad85d90..513590931cc5 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -1820,30 +1820,20 @@ static bool edid_block_is_zero(const void *edid)
>   	return !memchr_inv(edid, 0, EDID_LENGTH);
>   }
>   
> -/**
> - * drm_edid_are_equal - compare two edid blobs.
> - * @edid1: pointer to first blob
> - * @edid2: pointer to second blob
> - * This helper can be used during probing to determine if
> - * edid had changed.
> - */
> -static bool drm_edid_are_equal(const struct edid *edid1, const struct edid *edid2)
> +static bool drm_edid_eq(const struct drm_edid *drm_edid,
> +			const void *raw_edid, size_t raw_edid_size)
>   {
> -	int edid1_len, edid2_len;
> -	bool edid1_present = edid1 != NULL;
> -	bool edid2_present = edid2 != NULL;
> +	bool edid1_present = drm_edid && drm_edid->edid && drm_edid->size;
> +	bool edid2_present = raw_edid && raw_edid_size;
>   
>   	if (edid1_present != edid2_present)
>   		return false;
>   
> -	if (edid1) {
> -		edid1_len = edid_size(edid1);
> -		edid2_len = edid_size(edid2);
> -
> -		if (edid1_len != edid2_len)
> +	if (edid1_present) {
> +		if (drm_edid->size != raw_edid_size)
>   			return false;
>   
> -		if (memcmp(edid1, edid2, edid1_len))
> +		if (memcmp(drm_edid->edid, raw_edid, drm_edid->size))
>   			return false;
>   	}
>   
> @@ -6936,15 +6926,14 @@ static int _drm_edid_connector_property_update(struct drm_connector *connector,
>   	int ret;
>   
>   	if (connector->edid_blob_ptr) {
> -		const struct edid *old_edid = connector->edid_blob_ptr->data;
> -
> -		if (old_edid) {
> -			if (!drm_edid_are_equal(drm_edid ? drm_edid->edid : NULL, old_edid)) {
> -				connector->epoch_counter++;
> -				drm_dbg_kms(dev, "[CONNECTOR:%d:%s] EDID changed, epoch counter %llu\n",
> -					    connector->base.id, connector->name,
> -					    connector->epoch_counter);
> -			}
> +		const void *old_edid = connector->edid_blob_ptr->data;
> +		size_t old_edid_size = connector->edid_blob_ptr->length;
> +
> +		if (old_edid && !drm_edid_eq(drm_edid, old_edid, old_edid_size)) {
> +			connector->epoch_counter++;
> +			drm_dbg_kms(dev, "[CONNECTOR:%d:%s] EDID changed, epoch counter %llu\n",
> +				    connector->base.id, connector->name,
> +				    connector->epoch_counter);
>   		}
>   	}
>   

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)