On Thu, Jun 04, 2015 at 07:12:31PM +0530, Kausal Malladi wrote: > From: Kausal Malladi <Kausal.Malladi@xxxxxxxxx> > > This patch set adds color manager implementation in drm/i915 layer. > Color Manager is an extension in i915 driver to support color > correction/enhancement. Various Intel platforms support several > color correction capabilities. Color Manager provides abstraction > of these properties and allows a user space UI agent to > correct/enhance the display. So I did a first rough pass on the API itself. The big question that isn't solved at the moment is: do we want to try to do generic KMS properties for pre-LUT + matrix + post-LUT or not. "Generic" has 3 levels: 1/ Generic for all KMS drivers 2/ Generic for i915 supported platfoms 3/ Specific to each platform At this point, I'm quite tempted to say we should give 1/ a shot. We should be able to have pre-LUT + matrix + post-LUT on CRTC objects and guarantee that, when the drivers expose such properties, user space can at least give 8 bits LUT + 3x3 matrix + 8 bits LUT. It may be possible to use the "try" version of the atomic ioctl to explore the space of possibilities from a generic user space to use bigger LUTs as well. A HAL layer (which is already there in some but not all OSes) would still be able to use those generic properties to load "precision optimized" LUTs with some knowledge of the hardware. Option 3/ is, IMHO, a no-go, we should really try hard to limit the work we need to do per-platform, which means defining a common format for the values we give to the kernel. As stated in various places, 16.16 seems the format of choice, even for the LUTs as we have wide gamut support in some of the LUTs where we can map values > 1.0 to other values > 1.0. Another thing, the documentation of the interface needs to be a bit more crisp. For instance, we don't currently define the order in which the CSC and LUT transforms of this patch set are applied: is this a de-gamma LUT to do the CSC in linear space? but then that means the display is linear, oops. So it must be a post-CSC lut, but then we don't de-gamma sRGB (not technically a single gamma power curve for sRGB, but details, details) before applying a linear transform. So with this interface, we have to enforce the fbs are linear, losing dynamic range. I'm sure later patches would expose more properties, but as a stand-alone patch set, it would seem we can't do anything useful? -- Damien _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
