[PATCH 1/2] video/hdmi: Allow "empty" HDMI infoframes

[Andrzej Hajda]

On 03.07.2017 21:19, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> HDMI 2.0 Appendix F suggest that we should keep sending the infoframe
> when switching from 3D to 2D mode, even if the infoframe isn't strictly
> necessary (ie. not needed to transmit the VIC or stereo information).
> This is a workaround against some sinks that fail to realize that they
> should switch from 3D to 2D mode when the source stop transmitting
> the infoframe.
>
> Cc: Shashank Sharma <shashank.sharma at intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/video/hdmi.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
> index 1cf907ecded4..af0c8dad29eb 100644
> --- a/drivers/video/hdmi.c
> +++ b/drivers/video/hdmi.c
> @@ -341,10 +341,6 @@ ssize_t hdmi_vendor_infoframe_pack(struct hdmi_vendor_infoframe *frame,
>  	u8 *ptr = buffer;
>  	size_t length;
>  
> -	/* empty info frame */
> -	if (frame->vic == 0 && frame->s3d_struct == HDMI_3D_STRUCTURE_INVALID)
> -		return -EINVAL;
> -
>  	/* only one of those can be supplied */
>  	if (frame->vic != 0 && frame->s3d_struct != HDMI_3D_STRUCTURE_INVALID)
>  		return -EINVAL;
> @@ -352,8 +348,10 @@ ssize_t hdmi_vendor_infoframe_pack(struct hdmi_vendor_infoframe *frame,
>  	/* for side by side (half) we also need to provide 3D_Ext_Data */
>  	if (frame->s3d_struct >= HDMI_3D_STRUCTURE_SIDE_BY_SIDE_HALF)
>  		frame->length = 6;
> -	else
> +	else if (frame->vic != 0 || frame->s3d_struct != HDMI_3D_STRUCTURE_INVALID)
>  		frame->length = 5;
> +	else
> +		frame->length = 4;
>  
>  	length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;
>  
> @@ -372,14 +370,16 @@ ssize_t hdmi_vendor_infoframe_pack(struct hdmi_vendor_infoframe *frame,
>  	ptr[5] = 0x0c;
>  	ptr[6] = 0x00;
>  
> -	if (frame->vic) {
> -		ptr[7] = 0x1 << 5;	/* video format */
> -		ptr[8] = frame->vic;
> -	} else {
> +	if (frame->s3d_struct != HDMI_3D_STRUCTURE_INVALID) {
>  		ptr[7] = 0x2 << 5;	/* video format */
>  		ptr[8] = (frame->s3d_struct & 0xf) << 4;
>  		if (frame->s3d_struct >= HDMI_3D_STRUCTURE_SIDE_BY_SIDE_HALF)
>  			ptr[9] = (frame->s3d_ext_data & 0xf) << 4;
> +	} else if (frame->vic) {
> +		ptr[7] = 0x1 << 5;	/* video format */
> +		ptr[8] = frame->vic;
> +	} else {
> +		ptr[7] = 0x0 << 5;	/* video format */

Changed order of conditionals (vic,s3d versus s3d,vic) could result in
different output, but only in case of incorrect VSIFs, so probably harmless.

Reviewed-by: Andrzej Hajda <a.hajda at samsung.com>

 --
Regards
Andrzej

>  	}
>  
>  	hdmi_infoframe_set_checksum(buffer, length);