[v16 0/4] Add Colorspace connector property interface

Uma Shankar uma.shankar at intel.com
Wed Feb 13 07:05:07 UTC 2019

This patch series creates a new connector property to program
colorspace to sink devices. Modern sink devices support more
than 1 type of colorspace like 601, 709, BT2020 etc. This helps
to switch based on content type which is to be displayed. The
decision lies with compositors as to in which scenarios, a
particular colorspace will be picked.

This will be helpful mostly to switch to higher gamut colorspaces
like BT2020 when the media content is encoded as BT2020. Thereby
giving a good visual experience to users.

The expectation from userspace is that it should parse the EDID
and get supported colorspaces. Use this property and switch to the
one supported. Sink supported colorspaces should be retrieved by
userspace from EDID and driver will not explicitly expose them.

Basically the expectation from userspace is:
 - Set up CRTC DEGAMMA/CTM/GAMMA to convert to some sink
 - Set this new property to let the sink know what it
   converted the CRTC output to.
 - This property is just to inform sink what colorspace
   source is trying to drive.

Have tested this using xrandr by using below command:
xrandr --output HDMI2 --set "Colorspace" "BT2020_rgb"

v2: Addressed Ville and Maarten's review comments. Merged the 2nd
and 3rd patch into one common logical patch.

v3: Removed Adobe references from enum definitions as per
Ville, Hans Verkuil and Jonas Karlman suggestions. Changed
default to an unset state where driver will assign the colorspace
when not chosen by user, suggested by Ville and Maarten. Addressed
other misc review comments from Maarten. Split the changes to
have separate colorspace property for DP and HDMI.

v4: Addressed Chris and Ville's review comments, and created a
common colorspace property for DP and HDMI, filtered the list

v5: Modified the colorspace property creation helper to take
platform specific enum list based on the capabilities of the
platform as suggested by Shashank. With this there is no need
for segregation between DP and HDMI.

v6: Addressed Shashank's review comments.

v7: Added defines instead of enum in uapi as per Brian Starkey's
suggestion in order to go with string matching at userspace. Updated
the kernel doc as well with more details.

v8: Addressed Maarten's review comments.

v9: Removed macro defines from uapi as per Brian Starkey and Daniel
Stone's comments and moved to drm include file. Moved back to older
design with exposing all HDMI colorspaces to userspace since infoframe
capability is there even on legacy platforms, as per Ville's review

v10: Addressed Maarten' review comment, updated the RB from Maarten
and Jani Nikula's ack. Also fixed sparse warnings and checkpatch

v11: Addressed Ville's review comments. Modified MACRO names, added
infoframe helper for colorspace to drm layer. Added DCI-P3 colorspace
macro definitions defined in CTA 861.G. Currently linux/hdmi lacks
support for ACE formats, will be added as a separate series.

v12: Exported the helper API.

v13: As per Ville's suggestion, added separate CTA 861.G spec defined
HDMI specific macros. This is separate from user exposed enum values.
Fixed some macro naming inconsistencies.

v14: Appended BT709 and SMPTE 170M with YCC information as per Ville's
review comment to be clear and not to be confused with RGB. Added a check
to allow only RGB colorspaces to be set in infoframe through the colorspace
property, since there is no output csc property to control planar formats
and it will be added later.

v15: Fixed an error in one of the if check.

v16: Added bit wise macro for various fields of colorimetry for easier
understanding and review as per Ville's comments. Moved the same out of
header file to avoid any namespace issues. Dropped the check for planar
vs RGB and allow all the colorspaces.

Uma Shankar (4):
  drm: Add HDMI colorspace property
  drm: Add DP colorspace property
  drm: Add colorspace info to AVI Infoframe
  drm/i915: Attach colorspace property and enable modeset

 drivers/gpu/drm/drm_atomic_uapi.c      |   4 ++
 drivers/gpu/drm/drm_connector.c        | 104 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_edid.c             |  66 +++++++++++++++++++++
 drivers/gpu/drm/i915/intel_atomic.c    |   1 +
 drivers/gpu/drm/i915/intel_connector.c |   8 +++
 drivers/gpu/drm/i915/intel_drv.h       |   1 +
 drivers/gpu/drm/i915/intel_hdmi.c      |  13 +++++
 include/drm/drm_connector.h            |  49 ++++++++++++++++
 include/drm/drm_edid.h                 |   6 ++
 9 files changed, 252 insertions(+)


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