[PATCH 1/3] drm/edid: parse multiple CEA extension block

Lee, Shawn C shawn.c.lee at intel.com
Sun Feb 27 14:49:53 UTC 2022


On Saturday, February 26, 2022 1:47 AM, Ville Syrjälä wrote:
>On Thu, Feb 24, 2022 at 10:16:23PM +0800, Lee Shawn C wrote:
>> Try to find and parse more CEA ext blocks if edid->extensions is 
>> greater than one.
>> 
>> Cc: Jani Nikula <jani.nikula at linux.intel.com>
>> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
>> Cc: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>> Signed-off-by: Lee Shawn C <shawn.c.lee at intel.com>
>> ---
>>  drivers/gpu/drm/drm_edid.c | 110 
>> ++++++++++++++++++++-----------------
>>  1 file changed, 60 insertions(+), 50 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c 
>> index a504542238ed..19426f28b411 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -3353,16 +3353,14 @@ const u8 *drm_find_edid_extension(const struct edid *edid,
>>  	return edid_ext;
>>  }
>>  
>> -static const u8 *drm_find_cea_extension(const struct edid *edid)
>> +static const u8 *drm_find_cea_extension(const struct edid *edid, int 
>> +*ext_index)
>>  {
>>  	const struct displayid_block *block;
>>  	struct displayid_iter iter;
>>  	const u8 *cea;
>> -	int ext_index = 0;
>>  
>> -	/* Look for a top level CEA extension block */
>> -	/* FIXME: make callers iterate through multiple CEA ext blocks? */
>> -	cea = drm_find_edid_extension(edid, CEA_EXT, &ext_index);
>> +	/* Look for a CEA extension block from ext_index */
>> +	cea = drm_find_edid_extension(edid, CEA_EXT, ext_index);
>>  	if (cea)
>>  		return cea;
>>  
>> @@ -3643,10 +3641,10 @@ add_alternate_cea_modes(struct drm_connector *connector, struct edid *edid)
>>  	struct drm_device *dev = connector->dev;
>>  	struct drm_display_mode *mode, *tmp;
>>  	LIST_HEAD(list);
>> -	int modes = 0;
>> +	int modes = 0, ext_index = 0;
>>  
>>  	/* Don't add CEA modes if the CEA extension block is missing */
>> -	if (!drm_find_cea_extension(edid))
>> +	if (!drm_find_cea_extension(edid, &ext_index))
>>  		return 0;
>>  
>>  	/*
>> @@ -4321,46 +4319,58 @@ static void drm_parse_y420cmdb_bitmap(struct 
>> drm_connector *connector,  static int  add_cea_modes(struct 
>> drm_connector *connector, struct edid *edid)  {
>> -	const u8 *cea = drm_find_cea_extension(edid);
>> +	const u8 *cea = NULL;
>>  	const u8 *db, *hdmi = NULL, *video = NULL;
>>  	u8 dbl, hdmi_len, video_len = 0;
>> -	int modes = 0;
>> +	int modes = 0, ext_index = 0;
>>  
>> -	if (cea && cea_revision(cea) >= 3) {
>> -		int i, start, end;
>> +	for (;;) {
>> +		cea = drm_find_cea_extension(edid, &ext_index);
>
>Please split this into two patches:
>1. do the *ext_index stuff
>2. do the loop
>

Thanks for comment! Will split this patch to two in next version.

>>  
>> -		if (cea_db_offsets(cea, &start, &end))
>> -			return 0;
>> +		if (!cea)
>> +			break;
>>  
>> -		for_each_cea_db(cea, i, start, end) {
>> -			db = &cea[i];
>> -			dbl = cea_db_payload_len(db);
>> +		if (cea && cea_revision(cea) >= 3) {
>> +			int i, start, end;
>> +
>> +			if (cea_db_offsets(cea, &start, &end))
>> +				continue;
>>  
>> -			if (cea_db_tag(db) == VIDEO_BLOCK) {
>> -				video = db + 1;
>> -				video_len = dbl;
>> -				modes += do_cea_modes(connector, video, dbl);
>> -			} else if (cea_db_is_hdmi_vsdb(db)) {
>> -				hdmi = db;
>> -				hdmi_len = dbl;
>> -			} else if (cea_db_is_y420vdb(db)) {
>> -				const u8 *vdb420 = &db[2];
>> -
>> -				/* Add 4:2:0(only) modes present in EDID */
>> -				modes += do_y420vdb_modes(connector,
>> -							  vdb420,
>> -							  dbl - 1);
>> +			for_each_cea_db(cea, i, start, end) {
>> +				db = &cea[i];
>> +				dbl = cea_db_payload_len(db);
>> +
>> +				if (cea_db_tag(db) == VIDEO_BLOCK) {
>> +					video = db + 1;
>> +					video_len = dbl;
>> +					modes += do_cea_modes(connector, video, dbl);
>> +				} else if (cea_db_is_hdmi_vsdb(db)) {
>> +					hdmi = db;
>> +					hdmi_len = dbl;
>> +				} else if (cea_db_is_y420vdb(db)) {
>> +					const u8 *vdb420 = &db[2];
>> +
>> +					/* Add 4:2:0(only) modes present in EDID */
>> +					modes += do_y420vdb_modes(connector,
>> +								  vdb420,
>> +								  dbl - 1);
>> +				}
>>  			}
>>  		}
>> -	}
>>  
>> -	/*
>> -	 * We parse the HDMI VSDB after having added the cea modes as we will
>> -	 * be patching their flags when the sink supports stereo 3D.
>> -	 */
>> -	if (hdmi)
>> -		modes += do_hdmi_vsdb_modes(connector, hdmi, hdmi_len, video,
>> -					    video_len);
>> +		/*
>> +		 * We parse the HDMI VSDB after having added the cea modes as we will
>> +		 * be patching their flags when the sink supports stereo 3D.
>> +		 */
>> +		if (hdmi) {
>
>Looks like you're potentially using stale information here from previous loops. Please move all the possible variables to a tighter scope so this can't happen.
>

Yes, you are right! I will modify these codes and send patch v2 for review later.

Best regards,
Shawn

>> +			modes += do_hdmi_vsdb_modes(connector, hdmi, hdmi_len, video,
>> +						    video_len);
>> +			hdmi  = NULL;
>> +			video = NULL;
>> +			hdmi_len = 0;
>> +			video_len = 0;
>> +		}
>> +	}
>>  
>>  	return modes;
>>  }
>> @@ -4562,7 +4572,7 @@ static void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
>>  	uint8_t *eld = connector->eld;
>>  	const u8 *cea;
>>  	const u8 *db;
>> -	int total_sad_count = 0;
>> +	int total_sad_count = 0, ext_index = 0;
>>  	int mnl;
>>  	int dbl;
>>  
>> @@ -4571,7 +4581,7 @@ static void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
>>  	if (!edid)
>>  		return;
>>  
>> -	cea = drm_find_cea_extension(edid);
>> +	cea = drm_find_cea_extension(edid, &ext_index);
>>  	if (!cea) {
>>  		DRM_DEBUG_KMS("ELD: no CEA Extension found\n");
>>  		return;
>> @@ -4655,11 +4665,11 @@ static void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
>>   */
>>  int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads)  {
>> -	int count = 0;
>> +	int count = 0, ext_index = 0;
>>  	int i, start, end, dbl;
>>  	const u8 *cea;
>>  
>> -	cea = drm_find_cea_extension(edid);
>> +	cea = drm_find_cea_extension(edid, &ext_index);
>>  	if (!cea) {
>>  		DRM_DEBUG_KMS("SAD: no CEA Extension found\n");
>>  		return 0;
>> @@ -4717,11 +4727,11 @@ EXPORT_SYMBOL(drm_edid_to_sad);
>>   */
>>  int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb)  {
>> -	int count = 0;
>> +	int count = 0, ext_index = 0;
>>  	int i, start, end, dbl;
>>  	const u8 *cea;
>>  
>> -	cea = drm_find_cea_extension(edid);
>> +	cea = drm_find_cea_extension(edid, &ext_index);
>>  	if (!cea) {
>>  		DRM_DEBUG_KMS("SAD: no CEA Extension found\n");
>>  		return 0;
>> @@ -4813,10 +4823,10 @@ EXPORT_SYMBOL(drm_av_sync_delay);  bool 
>> drm_detect_hdmi_monitor(struct edid *edid)  {
>>  	const u8 *edid_ext;
>> -	int i;
>> +	int i, ext_index = 0;
>>  	int start_offset, end_offset;
>>  
>> -	edid_ext = drm_find_cea_extension(edid);
>> +	edid_ext = drm_find_cea_extension(edid, &ext_index);
>>  	if (!edid_ext)
>>  		return false;
>>  
>> @@ -4851,11 +4861,11 @@ EXPORT_SYMBOL(drm_detect_hdmi_monitor);
>>  bool drm_detect_monitor_audio(struct edid *edid)  {
>>  	const u8 *edid_ext;
>> -	int i, j;
>> +	int i, j, ext_index = 0;
>>  	bool has_audio = false;
>>  	int start_offset, end_offset;
>>  
>> -	edid_ext = drm_find_cea_extension(edid);
>> +	edid_ext = drm_find_cea_extension(edid, &ext_index);
>>  	if (!edid_ext)
>>  		goto end;
>>  
>> @@ -5177,9 +5187,9 @@ static void drm_parse_cea_ext(struct 
>> drm_connector *connector,  {
>>  	struct drm_display_info *info = &connector->display_info;
>>  	const u8 *edid_ext;
>> -	int i, start, end;
>> +	int i, start, end, ext_index = 0;
>>  
>> -	edid_ext = drm_find_cea_extension(edid);
>> +	edid_ext = drm_find_cea_extension(edid, &ext_index);
>>  	if (!edid_ext)
>>  		return;
>>  
>> --
>> 2.17.1
>
>--
>Ville Syrjälä
>Intel
>


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