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

[Thomas Zimmermann <tzimmermann@suse.de>]

Hi

Am 16.04.24 um 14:27 schrieb Jani Nikula:
> On Tue, 16 Apr 2024, Thomas Zimmermann <tzimmermann@suse.de> wrote:
>> 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.
> Ack.
>
> Thanks for the review. I'll hold of on resending these until there are
> some R-b's... I've send them a few times already with no comments. :(

Feel free to add

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

to the series.

Best regards
Thomas

>
> BR,
> Jani.
>
>> Best regards
>> Thomas
>>
>>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>>> ---
>>>    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)