[PATCH 00/11] drm/vkms: improve color curve LUTs precision

[Leandro Ribeiro]

Currently VKMS only supports uniform LUTs. Besides the userspace
provided LUTs, it also represents color curves with LUTs, as it can't
simply implement the continuous curve formulas (floating-point would be
required).

This adds support to represent color curves with non-uniform LUTs,
improving the precision significantly. It also provides a script
that was used to create these LUTs.

The optimized LUTs use more samples in regions where the interpolation
and quantization errors are higher (usually in regions with a steeper
slope). The LUT generator script compares different strategies and uses
greedy subdivision, which outperformed the other methods, to generate
the optimized LUTs for VKMS.

Leandro Ribeiro (11):
  drm/vkms: rename VKMS_LUT_SIZE to VKMS_GAMMA_LUT_SIZE
  drm/vkms: allow color curve LUTs to have different sizes
  drm/vkms: remove TEST_LUT_SIZE
  drm/vkms: remove linear_eotf
  drm/vkms: improve the way in which we access LUT member
  drm/vkms: rename struct vkms_color_lut::base to y
  drm/vkms: rename get_lut_index() to get_uniform_lut_index()
  drm/vkms: add support to non-uniform LUT for internal color curves
  drm/vkms: test sRGB and inverse sRGB LUTs using more samples
  drm/vkms: add script to create optimized LUTs for color curves
  drm/vkms: replace uniform sRGB LUT and its inverse with optimal ones

 .../gpu/drm/vkms/scripts/color-curve-lut.py   |  561 +++++++
 drivers/gpu/drm/vkms/tests/vkms_color_test.c  |   46 +-
 drivers/gpu/drm/vkms/vkms_composer.c          |  127 +-
 drivers/gpu/drm/vkms/vkms_composer.h          |    2 +-
 drivers/gpu/drm/vkms/vkms_crtc.c              |    4 +-
 drivers/gpu/drm/vkms/vkms_drv.c               |    2 +-
 drivers/gpu/drm/vkms/vkms_drv.h               |   13 +-
 drivers/gpu/drm/vkms/vkms_luts.c              | 1469 ++++++++---------
 drivers/gpu/drm/vkms/vkms_luts.h              |    3 -
 9 files changed, 1383 insertions(+), 844 deletions(-)
 create mode 100644 drivers/gpu/drm/vkms/scripts/color-curve-lut.py

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2.55.0