Appedix F of HDMI 2.0 says that some HDMI sink may fail to switch from
3D to 2D mode in a timely fashion if the source simply stops sending the
HDMI infoframe. The suggested workaround is to keep sending the
infoframe even when strictly not necessary (ie. no VIC and no S3D).
HDMI 1.4 does allow for this behaviour, stating that sending the
infoframe is optional in this case.
The infoframe was first specified in HDMI 1.4, so in theory sinks
predating that may not appreciate us sending an uknown infoframe
their way. To avoid regressions let's try to determine if the sink
supports the infoframe or not. Unfortunately there's no direct way
to do that, so instead we'll just check if we managed to parse any
HDMI 1.4 4k or stereo modes from the EDID, and if so we assume the
sink will accept the infoframe. Also if the EDID contains the HDMI
2.0 HDMI Forum VSDB we can assume the sink is prepared to receive
the infoframe.
v2: Fix getting has_hdmi_infoframe from display_info
Always fail constructing the infoframe if the display
possibly can't handle it
Cc: Shashank Sharma <shashank.sharma@intel.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171113170427.4150-3-ville.syrjala@linux.intel.com
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