drm/edid: split HDMI VSDB info and mode parsing

Separate the parsing of display info and modes from the HDMI VSDB. This
is prerequisite work for overall better separation of the two parsing
steps.

The info parsing is about figuring out whether the sink supports HDMI
infoframes. Since they were added in HDMI 1.4, assume the sink supports
HDMI infoframes if it has the HDMI_Video_present bit set (introduced in
HDMI 1.4). For details, see commit f1781e9b ("drm/edid: Allow HDMI
infoframe without VIC or S3D").

The logic is not exactly the same, but since it was somewhat heuristic
to begin with, assume this is close enough.

v2:
- Simplify to only check HDMI_Video_present bit (Ville)
- Drop cea_db_raw_size() helper (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/238e15f7ab15a86f7fd1812271dcaec9bc6e1506.1674144945.git.jani.nikula@intel.com

drivers/gpu/drm/drm_edid.c

@@ -4713,7 +4713,6 @@ static int hdmi_vsdb_latency_length(const u8 *db)
 static int
 do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len)
 {
-	struct drm_display_info *info = &connector->display_info;
 	int modes = 0, offset = 0, i, multi_present = 0, multi_len;
 	u8 vic_len, hdmi_3d_len = 0;
 	u16 mask;
@@ -4831,8 +4830,6 @@ do_hdmi_vsdb_modes(struct drm_connector *connector, const u8 *db, u8 len)
 	}
 
 out:
-	if (modes > 0)
-		info->has_hdmi_infoframe = true;
 	return modes;
 }
 
@@ -6153,6 +6150,7 @@ static void drm_parse_hdmi_deep_color_info(struct drm_connector *connector,
 	}
 }
 
+/* HDMI Vendor-Specific Data Block (HDMI VSDB, H14b-VSDB) */
 static void
 drm_parse_hdmi_vsdb_video(struct drm_connector *connector, const u8 *db)
 {
@@ -6166,6 +6164,15 @@ drm_parse_hdmi_vsdb_video(struct drm_connector *connector, const u8 *db)
 	if (len >= 7)
 		info->max_tmds_clock = db[7] * 5000;
 
+	/*
+	 * Try to infer whether the sink supports HDMI infoframes.
+	 *
+	 * HDMI infoframe support was first added in HDMI 1.4. Assume the sink
+	 * supports infoframes if HDMI_Video_present is set.
+	 */
+	if (len >= 8 && db[8] & BIT(5))
+		info->has_hdmi_infoframe = true;
+
 	drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s] HDMI: DVI dual %d, max TMDS clock %d kHz\n",
 		    connector->base.id, connector->name,
 		    info->dvi_dual, info->max_tmds_clock);