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Commit 7ebe1963 authored by Lespiau, Damien's avatar Lespiau, Damien Committed by Dave Airlie
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drm/edid: Parse the HDMI CEA block and look for 4k modes 



HDMI 1.4 adds 4 "4k x 2k" modes in the the CEA vendor specific block.

With this commit, we now parse this block and expose the 4k modes that
we find there.

v2: Fix the "4096x2160" string (nice catch!), add comments about
    do_hdmi_vsdb_modes() arguments and make it clearer that offset is
    relative to the end of the required fields of the HDMI VSDB
    (Ville Syrjälä)

v3: Fix 'Unknow' typo (Simon Farnsworth)

Signed-off-by: default avatarDamien Lespiau <damien.lespiau@intel.com>
Tested-by: default avatarCancan Feng <cancan.feng@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67030


Reviewed-by: default avatarSimon Farnsworth <simon.farnsworth@onelan.co.uk>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarDave Airlie <airlied@gmail.com>
parent 13ac3f55

drivers/gpu/drm/drm_edid.c

+109 −15
Original line number Diff line number Diff line
@@ -931,6 +931,36 @@ static const struct drm_display_mode edid_cea_modes[] = { 
	 .vrefresh = 100, },

};



/*

 * HDMI 1.4 4k modes.

 */

static const struct drm_display_mode edid_4k_modes[] = {

	/* 1 - 3840x2160@30Hz */

	{ DRM_MODE("3840x2160", DRM_MODE_TYPE_DRIVER, 297000,

		   3840, 4016, 4104, 4400, 0,

		   2160, 2168, 2178, 2250, 0,

		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),

	  .vrefresh = 30, },

	/* 2 - 3840x2160@25Hz */

	{ DRM_MODE("3840x2160", DRM_MODE_TYPE_DRIVER, 297000,

		   3840, 4896, 4984, 5280, 0,

		   2160, 2168, 2178, 2250, 0,

		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),

	  .vrefresh = 25, },

	/* 3 - 3840x2160@24Hz */

	{ DRM_MODE("3840x2160", DRM_MODE_TYPE_DRIVER, 297000,

		   3840, 5116, 5204, 5500, 0,

		   2160, 2168, 2178, 2250, 0,

		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),

	  .vrefresh = 24, },

	/* 4 - 4096x2160@24Hz (SMPTE) */

	{ DRM_MODE("4096x2160", DRM_MODE_TYPE_DRIVER, 297000,

		   4096, 5116, 5204, 5500, 0,

		   2160, 2168, 2178, 2250, 0,

		   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),

	  .vrefresh = 24, },

};



/*** DDC fetch and block validation ***/



static const u8 edid_header[] = {
@@ -2465,6 +2495,68 @@ do_cea_modes(struct drm_connector *connector, const u8 *db, u8 len) 
	return modes;

}



/*

 * do_hdmi_vsdb_modes - Parse the HDMI Vendor Specific data block

 * @connector: connector corresponding to the HDMI sink

 * @db: start of the CEA vendor specific block

 * @len: length of the CEA block payload, ie. one can access up to db[len]

 *

 * Parses the HDMI VSDB looking for modes to add to @connector.

 */

static int

do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len)

{

	struct drm_device *dev = connector->dev;

	int modes = 0, offset = 0, i;

	u8 vic_len;



	if (len < 8)

		goto out;



	/* no HDMI_Video_Present */

	if (!(db[8] & (1 << 5)))

		goto out;



	/* Latency_Fields_Present */

	if (db[8] & (1 << 7))

		offset += 2;



	/* I_Latency_Fields_Present */

	if (db[8] & (1 << 6))

		offset += 2;



	/* the declared length is not long enough for the 2 first bytes

	 * of additional video format capabilities */

	offset += 2;

	if (len < (8 + offset))

		goto out;



	vic_len = db[8 + offset] >> 5;



	for (i = 0; i < vic_len && len >= (9 + offset + i); i++) {

		struct drm_display_mode *newmode;

		u8 vic;



		vic = db[9 + offset + i];



		vic--; /* VICs start at 1 */

		if (vic >= ARRAY_SIZE(edid_4k_modes)) {

			DRM_ERROR("Unknown HDMI VIC: %d\n", vic);

			continue;

		}



		newmode = drm_mode_duplicate(dev, &edid_4k_modes[vic]);

		if (!newmode)

			continue;



		drm_mode_probed_add(connector, newmode);

		modes++;

	}



out:

	return modes;

}



static int

cea_db_payload_len(const u8 *db)

{
@@ -2496,6 +2588,21 @@ cea_db_offsets(const u8 *cea, int *start, int *end) 
	return 0;

}



static bool cea_db_is_hdmi_vsdb(const u8 *db)

{

	int hdmi_id;



	if (cea_db_tag(db) != VENDOR_BLOCK)

		return false;



	if (cea_db_payload_len(db) < 5)

		return false;



	hdmi_id = db[1] | (db[2] << 8) | (db[3] << 16);



	return hdmi_id == HDMI_IDENTIFIER;

}



#define for_each_cea_db(cea, i, start, end) \

	for ((i) = (start); (i) < (end) && (i) + cea_db_payload_len(&(cea)[(i)]) < (end); (i) += cea_db_payload_len(&(cea)[(i)]) + 1)
@@ -2519,6 +2626,8 @@ add_cea_modes(struct drm_connector *connector, struct edid *edid) 


			if (cea_db_tag(db) == VIDEO_BLOCK)

				modes += do_cea_modes(connector, db + 1, dbl);

			else if (cea_db_is_hdmi_vsdb(db))

				modes += do_hdmi_vsdb_modes(connector, db, dbl);

		}

	}
@@ -2571,21 +2680,6 @@ monitor_name(struct detailed_timing *t, void *data) 
		*(u8 **)data = t->data.other_data.data.str.str;

}



static bool cea_db_is_hdmi_vsdb(const u8 *db)

{

	int hdmi_id;



	if (cea_db_tag(db) != VENDOR_BLOCK)

		return false;



	if (cea_db_payload_len(db) < 5)

		return false;



	hdmi_id = db[1] | (db[2] << 8) | (db[3] << 16);



	return hdmi_id == HDMI_IDENTIFIER;

}



/**

 * drm_edid_to_eld - build ELD from EDID

 * @connector: connector corresponding to the HDMI/DP sink