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

[Hans Verkuil]

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.

> Sadly the spec doesn't seem to forbid sending an overly long infoframe
> as long it's padded with 0. Would have been nicer for extending it if
> that sort of thing was forbidden. But I guess everything can be solved
> with flags. Not that I expect anyone to extend it anymore now that
> HDMI 2.0 has specified a totally new infoframe.
> 
>>
>> The current code thinks anything other than 5 or 6 is an error,
>> but larger values are allowed by the specification. So support
>> that here as well.

Can you add this line here (I thought I mentioned it, but it appears
I forgot it):

"Support for larger Vendor InfoFrames is also needed for HDMI_FORUM_IEEE_OUI
Vendor InfoFrames."

Thank you,

	Hans

>>
>> Signed-off-by: Hans Verkuil <hansverk at cisco.com>
>> ---
>>  drivers/video/hdmi.c | 3 +--
>>  include/linux/hdmi.h | 1 +
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
>> index 1cf907ecded4..61f803f75a47 100644
>> --- a/drivers/video/hdmi.c
>> +++ b/drivers/video/hdmi.c
>> @@ -1164,8 +1164,7 @@ hdmi_vendor_any_infoframe_unpack(union hdmi_vendor_any_infoframe *frame,
>>  	struct hdmi_vendor_infoframe *hvf = &frame->hdmi;
>>  
>>  	if (ptr[0] != HDMI_INFOFRAME_TYPE_VENDOR ||
>> -	    ptr[1] != 1 ||
>> -	    (ptr[2] != 5 && ptr[2] != 6))
>> +	    ptr[1] != 1 || ptr[2] < 5 || ptr[2] > HDMI_VENDOR_INFOFRAME_SIZE)
>>  		return -EINVAL;
>>  
>>  	length = ptr[2];
>> diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h
>> index d271ff23984f..14d3531a0eda 100644
>> --- a/include/linux/hdmi.h
>> +++ b/include/linux/hdmi.h
>> @@ -40,6 +40,7 @@ enum hdmi_infoframe_type {
>>  #define HDMI_AVI_INFOFRAME_SIZE    13
>>  #define HDMI_SPD_INFOFRAME_SIZE    25
>>  #define HDMI_AUDIO_INFOFRAME_SIZE  10
>> +#define HDMI_VENDOR_INFOFRAME_SIZE 31
>>  
>>  #define HDMI_INFOFRAME_SIZE(type)	\
>>  	(HDMI_INFOFRAME_HEADER_SIZE + HDMI_ ## type ## _INFOFRAME_SIZE)
>> -- 
>> 2.14.1
>