On Monday, August 31, 2020 3:48 PM, Ville Syrjälä ville.syrjala@linux.intel.com wrote:
It doesn't seem like this IGT test's goal is to exercise support for gamma LUTs. Does the test just tries to reset the gamma LUT to linear? If so, I think the IGT test should be fixed to ignore "I don't support gamma" errors.
It seems like that IGT test pixel-format is to make gamma lut like below. for (i = 0; i < lut_size; i++) lut[i] = (i * 0xffff / (lut_size - 1)) & mask; And set this table to drm driver. and test begins. It's the test about pixel format. I think you're right. It's not about gamma lut.
The point of the gamma LUT stuff in the pixel format test is to throw away a bunch of the lsbs so that the test passes when the result is "close enough" to the 8bpc RGB reference image. Without it we would never get a crc match when testing non-8bpc or YCbCr formats.
OK, that makes sense. Would it be sensible to:
- Don't set gamma if the pixel format being tested is 8bpc - Make the test skip if the pixel format is >8bpc and gamma isn't supported