On Sun, Dec 12, 2021 at 11:33:31PM +0800, Lee Shawn C wrote: > According to CEA-861-F chapter 7.5.4. It says "The VSDB shall contain the > 3 bytes of the IEEE OUI as well as any additional payload bytes needed." > Now DRM driver check HDMI OUI but VSDB payload size at least five bytes. > That may caused some HDMI monitors' audio feature can't be enabled. > Because of they only have three bytes payload (OUI only) in VSDB. HDMI 1.4a says "Sinks shall contain an HDMI VSDB minimally containing a 2-byte Source Physical Address field following the 24-bit identifier. ... The minimum value of N (length) is 5 and the maximum value of N is 31." Do you actually have an EDID that violates that? > > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Cc: Adam Jackson <ajax@xxxxxxxxxx> > Cc: Dave Airlie <airlied@xxxxxxxxxx> > Signed-off-by: Lee Shawn C <shawn.c.lee@xxxxxxxxx> > --- > drivers/gpu/drm/drm_edid.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 12893e7be89b..5aa4a6bf4a13 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -4205,7 +4205,7 @@ static bool cea_db_is_hdmi_vsdb(const u8 *db) > if (cea_db_tag(db) != VENDOR_BLOCK) > return false; > > - if (cea_db_payload_len(db) < 5) > + if (cea_db_payload_len(db) < 3) > return false; > > return oui(db[3], db[2], db[1]) == HDMI_IEEE_OUI; > -- > 2.31.1 -- Ville Syrjälä Intel
