From: Cooper Chiou <cooper.ch...@intel.com>

commit 5662abf6e21338be6d085d6375d3732ac6147fd2 upstream.

Tag code stored in bit7:5 for CTA block byte[3] is not the same as
CEA extension block definition. Only check CEA block has
basic audio support.

v3: update commit message.

Cc: sta...@vger.kernel.org
Cc: Jani Nikula <jani.nik...@intel.com>
Cc: Shawn C Lee <shawn.c....@intel.com>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>
Signed-off-by: Cooper Chiou <cooper.ch...@intel.com>
Signed-off-by: Lee Shawn C <shawn.c....@intel.com>
Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Reviewed-by: Jani Nikula <jani.nik...@intel.com>
Signed-off-by: Jani Nikula <jani.nik...@intel.com>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20220324061218.32739-1-shawn.c....@intel.com
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/gpu/drm/drm_edid.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -4848,7 +4848,8 @@ bool drm_detect_monitor_audio(struct edi
        if (!edid_ext)
                goto end;
 
-       has_audio = ((edid_ext[3] & EDID_BASIC_AUDIO) != 0);
+       has_audio = (edid_ext[0] == CEA_EXT &&
+                   (edid_ext[3] & EDID_BASIC_AUDIO) != 0);
 
        if (has_audio) {
                DRM_DEBUG_KMS("Monitor has basic audio support\n");


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