> > FreeSync HDR provides the big benefit that display behavior is more > > predictable, and the "native" signal doesn't waste any color resolution on > > out of bounds colors or luminance values. > > > > The property has two values right now, "Disabled" and "FreeSync 2 Native". > > If any other FreeSync HDR modes exist or will be added at some point, they > > can be added as new enum values as well. > > How should this interact with the connector properties "Colorspace" and > "HDR_OUTPUT_METADATA"? >From experimentation, my display seems to ignore the colorspace and "traditional gamma SDR" in HDR_OUTPUT_METADATA while FreeSync HDR is active. Setting the eotf to PQ however turns FreeSync HDR off and switches the display into conventional HDR mode.
Making any definite statements about this will require someone from AMD to provide documentation, which is why I didn't put anything explicit about it into the patch. > Does one override the other when they disagree? Is userspace > expected to program all of them into agreement? Should the atomic > commit fail if they disagree? Just like with HDR_OUTPUT_METADATA, it should just be up to userspace to set things up in a way that works with the display. > What about instead of a new property, make a new value called "Native" > for "Colorspace", and require userspace to set HDR_OUTPUT_METADATA eotf > field to "traditional gamma HDR"? This might be a silly idea, but I'd > like to hear why. Alternatively, HDR_OUTPUT_METADATA could use a new > 'metadata_type' value for the eotf. I thought (and hoped) it would end up being just like that, but at least my display doesn't support the "traditional gamma HDR" at all. If you set it anyways, it seems to just fall back to "traditional gamma SDR". As HDR output metadata and colorspace have been more or less just passed through to the display without modifications so far, I'd rather not have the kernel step in between and try to translate things - especially not if there's actually displays out there that do support the "traditional gamma HDR", in which case that value may become ambiguous. - Xaver
