Commit cba83c1f authored by Jani Nikula's avatar Jani Nikula
Browse files

drm/edid: add helper for HDMI VSDB audio latency field length 



Add a helper for skipping the HDMI VSDB audio latency fields.

There's a functional change for HDMI VSDB blocks that do not respect the
spec: "I_Latency_Fields_Present shall be zero if Latency_Fields_Present
is zero". We assume this to hold when skipping the latency fields, and
ignore non-zero I_Latency_Fields_Present if Latency_Fields_Present is
zero.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/da4293203ef2ddeb0bf66a2bfdbc129ab609c543.1672826282.git.jani.nikula@intel.com
parent 1ee3e217

drivers/gpu/drm/drm_edid.c

+11 −7
Original line number Diff line number Diff line
@@ -4695,6 +4695,16 @@ static bool hdmi_vsdb_i_latency_present(const u8 *db) 
	return hdmi_vsdb_latency_present(db) && db[8] & BIT(6);

}



static int hdmi_vsdb_latency_length(const u8 *db)

{

	if (hdmi_vsdb_i_latency_present(db))

		return 4;

	else if (hdmi_vsdb_latency_present(db))

		return 2;

	else

		return 0;

}



/*

 * do_hdmi_vsdb_modes - Parse the HDMI Vendor Specific data block

 * @connector: connector corresponding to the HDMI sink
@@ -4720,13 +4730,7 @@ do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len) 
	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;

	offset += hdmi_vsdb_latency_length(db);



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

	 * of additional video format capabilities */