Re: [Intel-gfx] [PATCH 03/12] drm/edid: refactor EDID block status printing

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 07 Apr 2022, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> On Thu, Apr 07, 2022 at 12:14:29PM +0300, Jani Nikula wrote:
>> Split out a function to log EDID block status. The printouts get changed
>> slightly.
>> 
>> Unfortunately, not all users will have struct drm_device available, so
>> we convert to pr_* debug logging instead of drm device based logging.
>> 
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/drm_edid.c | 75 ++++++++++++++++++++++++++------------
>>  1 file changed, 51 insertions(+), 24 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> index f062d1715ec3..3d04d63464ba 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -1729,6 +1729,50 @@ static bool edid_block_valid(const void *block, bool base)
>>  				       edid_block_tag(block));
>>  }
>>  
>> +static void edid_block_status_print(enum edid_block_status status,
>> +				    const struct edid *block,
>> +				    int block_num)
>> +{
>> +	switch (status) {
>> +	case EDID_BLOCK_OK:
>> +		break;
>> +	case EDID_BLOCK_NULL:
>> +		pr_debug("EDID block %d pointer is NULL\n", block_num);
>> +		break;
>> +	case EDID_BLOCK_ZERO:
>> +		pr_notice("EDID block %d is all zeroes\n", block_num);
>> +		break;
>> +	case EDID_BLOCK_HEADER_CORRUPT:
>> +		pr_notice("EDID has corrupt header\n");
>> +		break;
>> +	case EDID_BLOCK_HEADER_REPAIR:
>> +		pr_debug("EDID corrupt header needs repair\n");
>> +		break;
>> +	case EDID_BLOCK_HEADER_FIXED:
>> +		pr_debug("EDID corrupt header fixed\n");
>> +		break;
>> +	case EDID_BLOCK_CHECKSUM:
>> +		if (edid_block_status_valid(status, edid_block_tag(block))) {
>> +			pr_debug("EDID block %d (tag 0x%02x) checksum is invalid, remainder is %d, ignoring\n",
>> +				 block_num, edid_block_tag(block),
>> +				 edid_block_compute_checksum(block));
>> +		} else {
>> +			pr_notice("EDID block %d (tag 0x%02x) checksum is invalid, remainder is %d\n",
>> +				  block_num, edid_block_tag(block),
>> +				  edid_block_compute_checksum(block));
>> +		}
>> +		break;
>> +	case EDID_BLOCK_VERSION:
>> +		pr_notice("EDID has major version %d, instead of 1\n",
>> +			  block->version);
>> +		break;
>> +	default:
>> +		pr_debug("EDID block %d unknown edid block status code %d\n",
>> +			 block_num, status);
>
> Maybe this should complaing a bit more loudly. Indicates a bug in the
> code no?

Sent v2 with WARN().

Thanks,
Jani


>
> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
>> +		break;
>> +	}
>> +}
>> +
>>  /**
>>   * drm_edid_block_valid - Sanity check the EDID block (base or extension)
>>   * @raw_edid: pointer to raw EDID block
>> @@ -1775,33 +1819,16 @@ bool drm_edid_block_valid(u8 *_block, int block_num, bool print_bad_edid,
>>  			*edid_corrupt = true;
>>  	}
>>  
>> +	edid_block_status_print(status, block, block_num);
>> +
>>  	/* Determine whether we can use this block with this status. */
>>  	valid = edid_block_status_valid(status, edid_block_tag(block));
>>  
>> -	/* Some fairly random status printouts. */
>> -	if (status == EDID_BLOCK_CHECKSUM) {
>> -		if (valid) {
>> -			DRM_DEBUG("EDID block checksum is invalid, remainder is %d\n",
>> -				  edid_block_compute_checksum(block));
>> -			DRM_DEBUG("Assuming a KVM switch modified the block but left the original checksum\n");
>> -		} else if (print_bad_edid) {
>> -			DRM_NOTE("EDID block checksum is invalid, remainder is %d\n",
>> -				 edid_block_compute_checksum(block));
>> -		}
>> -	} else if (status == EDID_BLOCK_VERSION) {
>> -		DRM_NOTE("EDID has major version %d, instead of 1\n",
>> -			 block->version);
>> -	}
>> -
>> -	if (!valid && print_bad_edid) {
>> -		if (status == EDID_BLOCK_ZERO) {
>> -			pr_notice("EDID block is all zeroes\n");
>> -		} else {
>> -			pr_notice("Raw EDID:\n");
>> -			print_hex_dump(KERN_NOTICE,
>> -				       " \t", DUMP_PREFIX_NONE, 16, 1,
>> -				       block, EDID_LENGTH, false);
>> -		}
>> +	if (!valid && print_bad_edid && status != EDID_BLOCK_ZERO) {
>> +		pr_notice("Raw EDID:\n");
>> +		print_hex_dump(KERN_NOTICE,
>> +			       " \t", DUMP_PREFIX_NONE, 16, 1,
>> +			       block, EDID_LENGTH, false);
>>  	}
>>  
>>  	return valid;
>> -- 
>> 2.30.2

-- 
Jani Nikula, Intel Open Source Graphics Center