[PATCH 1/2] drivers/video/hdmi: allow for larger-than-needed vendor IF

[Hans Verkuil]

On 11/21/17 16:27, Ville Syrjälä wrote:
> On Mon, Nov 20, 2017 at 04:02:14PM +0100, Hans Verkuil wrote:
>> On 11/20/2017 03:51 PM, Ville Syrjälä wrote:
>>> On Mon, Nov 20, 2017 at 02:41:28PM +0100, Hans Verkuil wrote:
>>>> From: Hans Verkuil <hansverk at cisco.com>
>>>>
>>>> Some devices (Windows Intel driver!) send a Vendor InfoFrame that
>>>> uses a payload length of 0x1b instead of the length of 5 or 6
>>>> that the unpack code expects. The InfoFrame is padded with 0 by
>>>> the source.
>>>
>>> So it doesn't put any 3D_Metadata stuff in there? We don't see to
>>> have code to parse/generate any of that.
>>
>> I can't remember if it puts any 3D stuff in there. Let me know if you
>> want me to check this later this week.
> 
> Would be nice to know.
> 
> I guess we should really add code to parse/generate that stuff too,
> otherwise we're going to be lying when we unpack an infoframe with that
> stuff present.
> 

Hmm, I can't reproduce this anymore. We did observe it but I can't
remember with which hardware or graphics driver version.

Testing with a Windows 10 Intel laptop with recent drivers just showed
either an empty vendor InfoFrame with a 1080p EDID or a vendor InfoFrame
that sets the HDMI VIC to 1 for a 4kp30 EDID.

The length is 5 in both cases.

Testing with a different laptop gave a vendor InfoFrame with HDMI VIC 1 and
a length of 6.

Regards,

	Hans