[PATCH v2 00/21] Enable Colorspace connector property in amdgpu

[Harry Wentland]

This patchset enables the DP and HDMI infoframe properties
in amdgpu.

The first two patches are not completely related to the rest. The
first patch allows for HDR_OUTPUT_METADATA with EOTFs that are
unknown in the kernel.

The second one prints a connector's max_bpc as part of the atomic
state debugfs print.

The following patches rework the connector colorspace code to
1) allow for easy printing of the colorspace in the drm_atomic
   state debugfs, and
2) allow drivers to specify the supported colorspaces on a
   connector.

The rest of the patches deal with the Colorspace enablement
in amdgpu.

Why do drivers need to specify supported colorspaces? The amdgpu
driver needs support for RGB-to-YCbCr conversion when we drive
the display in YCbCr. This is currently not implemented for all
colorspaces.

Since the Colorspace property didn't have an IGT test I added
one to kms_hdr. The relevant patchset can be found on the IGT
mailing list or on
https://gitlab.freedesktop.org/hwentland/igt-gpu-tools/-/tree/hdr-colorimetry

We tested v1 of the patchset and confirmed that the infoframes
are as expected for both DP and HDMI when running the IGT
colorimetry tests.

Open Items
----------

A couple comments from Pekka about colorspace documentation are
left unaddressed. I hope they won't block merging this set but
should still be addressed separately.

Pekka's questions really got me thinking of how this colorspace
property should be used and working with it more closely with
Joshua who is enabling HDR in gamescope made me wonder even more.

Uma, is there a (canonical, upstream) userspace that uses this
property that I can look at to understand more?

One of the key challenges that is currently not addressed is that
userspace is expected to pick a colorspace format straight from the
list of definitions out of the DP or HDMI spec. But the kernel
driver are the ones deciding on the output encoding (RGB, YCBCR444,
YCBCR420, etc.). So there is no way for userspace to decide correctly
between, for example, BT2020_RGB, BT2020_CYCC, BT2020_YCC.

So we end up in a scenario where gamescope sets BT2020_RGB but we
output YCBCR444 so have to correct the colorspace value to
BT2020_YCC. This in turn breaks the colorspace IGT tests I
wrote. I don't think "fixing" the IGT tests to accept this is
the right thing to do.

The way it stands this patchset allows us to specify the output
colorspace on amdgpu and we try to do the right thing, but I don't
thing the way the colorspace property is defined is right. We're trying
to expose things to userspace that should be under driver control. A
much better approach would be to give userspace options for colorspace
that are not tied to DP or HDMI specs, i.e., sRGB, BT709, BT2020, etc.,
and have the driver do the right thing to fill the infoframe, e.g., by
picking BT2020_YCC if the requested colorspace is BT2020 and the
is YCBCR444.

If no upstream userspace currently makes use of this property I
can make that change, i.e., no longer tie the colorspace property
directly to the infoframe and reduce the options to sRGB, BT709,
BT601, and BT2020 (and possibly opRGB).

v2:
- Tested with DP and HDMI analyzers
- Confirmed driver will fallback to lower bpc when needed
- Dropped hunk to set HDMI AVI infoframe as it was a no-op
- Fixed BT.2020 YCbCr colorimetry (JoshuaAshton)
- Simplify initialization of supported colorspaces (Jani)
- Fix kerneldoc (kernel test robot)

Cc: Pekka Paalanen <ppaalanen at gmail.com>
Cc: Sebastian Wick <sebastian.wick at redhat.com>
Cc: Vitaly.Prosyak at amd.com
Cc: Uma Shankar <uma.shankar at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Joshua Ashton <joshua at froggi.es>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Michel Dänzer <michel.daenzer at mailbox.org>
Cc: dri-devel at lists.freedesktop.org
Cc: amd-gfx at lists.freedesktop.org

Harry Wentland (16):
  drm/display: Don't block HDR_OUTPUT_METADATA on unknown EOTF
  drm/connector: print max_requested_bpc in state debugfs
  drm/connector: Drop COLORIMETRY_NO_DATA
  drm/connector: Convert DRM_MODE_COLORIMETRY to enum
  drm/connector: Pull out common create_colorspace_property code
  drm/connector: Allow drivers to pass list of supported colorspaces
  drm/connector: Print connector colorspace in state debugfs
  drm/amd/display: Always pass connector_state to stream validation
  drm/amd/display: Register Colorspace property for DP and HDMI
  drm/amd/display: Signal mode_changed if colorspace changed
  drm/amd/display: Send correct DP colorspace infopacket
  drm/amd/display: Add support for explicit BT601_YCC
  drm/amd/display: Add debugfs for testing output colorspace
  drm/amd/display: Add default case for output_color_space switch
  drm/amd/display: Don't restrict bpc to 8 bpc
  drm/amd/display: Format input and output CSC matrix

Joshua Ashton (5):
  drm/amd/display: Always set crtcinfo from create_stream_for_sink
  drm/amd/display: Fallback to 2020_YCBCR if the pixel encoding is not
    RGB
  drm/amd/display: Refactor avi_info_frame colorimetry determination
  drm/amd/display: Calculate output_color_space after pixel encoding
    adjustment
  drm/amd/display: Fix COLOR_SPACE_YCBCR2020_TYPE matrix

 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  90 ++++++---
 .../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c |  57 ++++++
 .../drm/amd/display/dc/core/dc_hw_sequencer.c |  38 ++--
 .../gpu/drm/amd/display/dc/core/dc_resource.c |  28 ++-
 drivers/gpu/drm/amd/display/dc/inc/hw/dpp.h   |  54 +++--
 drivers/gpu/drm/display/drm_hdmi_helper.c     |   8 +-
 drivers/gpu/drm/drm_atomic.c                  |   2 +
 drivers/gpu/drm/drm_connector.c               | 189 ++++++++++--------
 .../gpu/drm/i915/display/intel_connector.c    |   4 +-
 drivers/gpu/drm/vc4/vc4_hdmi.c                |   2 +-
 include/drm/display/drm_dp.h                  |   2 +-
 include/drm/drm_connector.h                   |  57 +++---
 12 files changed, 345 insertions(+), 186 deletions(-)

--
2.39.0