[RFC 1/3] drm: Add colorspace property

[Shankar, Uma]

>-----Original Message-----
>From: Adam Jackson [mailto:ajax at redhat.com]
>Sent: Wednesday, August 1, 2018 1:24 AM
>To: Shankar, Uma <uma.shankar at intel.com>; intel-gfx at lists.freedesktop.org;
>dri-devel at lists.freedesktop.org
>Cc: Syrjala, Ville <ville.syrjala at intel.com>; Lankhorst, Maarten
><maarten.lankhorst at intel.com>
>Subject: Re: [RFC 1/3] drm: Add colorspace property
>
>On Tue, 2018-07-24 at 21:15 +0530, Uma Shankar wrote:
>
>> --- a/include/uapi/drm/drm_mode.h
>> +++ b/include/uapi/drm/drm_mode.h
>> @@ -209,6 +209,17 @@
>>  #define DRM_MODE_CONTENT_PROTECTION_DESIRED     1
>>  #define DRM_MODE_CONTENT_PROTECTION_ENABLED     2
>>
>> +enum extended_colorimetry {
>> +	EXTENDED_COLORIMETRY_XV_YCC_601 = 0,
>> +	EXTENDED_COLORIMETRY_XV_YCC_709,
>> +	EXTENDED_COLORIMETRY_S_YCC_601,
>> +	EXTENDED_COLORIMETRY_ADOBE_YCC_601,
>> +	EXTENDED_COLORIMETRY_ADOBE_RGB,
>> +	EXTENDED_COLORIMETRY_BT2020_RGB,
>> +	EXTENDED_COLORIMETRY_BT2020_YCC,
>> +	EXTENDED_COLORIMETRY_BT2020_CYCC,
>> +};
>
>This doesn't give any way to distinguish "not set" from BT.601, which I'm not sure
>I like.

This enum gives a list of all possible colorspace which can be set on the sink device.
The compositors/userspace can choose one of them, based on the capabilities of sink
as well as based on rendering/blending policies which are designed to take advantage
of hardware resources available.

If you suggest to add something like NO_COLORSPACE_SET = -1, I can add that to this
enum list.

>
>Is this enum simply built to match the values you're injecting into the InfoFrame?
Yes they are as per HDMI SPEC defined Infoframe. This can directly be assigned to create
the equivalent infoframe.

>Would we need a different enum for DisplayPort?
DP will define a SDP packet to pass this info. From userspace, we can still pass this
enum value, as part of SDP packet creation DP driver can pick equivalent value as per DP spec
(which may be different from this enum value). But driver will still know as to what
colorspace is requested by userspace. 

>
>- ajax