[Intel-gfx] [PATCH 0/6] Intel Color Manager Framework

[Sharma, Shashank]

On Thu, Feb 20, 2014 at 5:11 AM, Ville Syrjälä <ville.syrjala at linux.intel.com<mailto:ville.syrjala at linux.intel.com>> wrote:
On Thu, Feb 20, 2014 at 06:07:21PM +0530, Shashank Sharma wrote:
>> Color manager is a new framework in i915 driver, which provides
>> a unified interface for various color correction methods supported
>> by intel hardwares. The high level overview of this change is:

>Would have been good to discuss this idea before implementing it. The
>plan is to use kms properties for this kind of stuff which allows us
>to hook it up with the upcoming atomic modeset API. Just yesterday there
>was some discussion on #dri-devel about exposing user settable blob
>properties even before the atomic modeset API lands (it was always the
>plan for the atomic modeset API anyway). So based on a cursory glance,
>this looks like it's going in the wrong direction.

+1. We'e looking into hooking up color correction controls, and if the interface isn't standard our user space won't be portable across drivers. There are multiple reasons for using drm properties:
- the KMS interface already provides a way to set the gamma ramp, which this code seems to replicate.

The current KMS interface just initializes the gamma soft LUT palette registers, in 8 bit mode corresponding to unit gamma. It's impossible to apply accurate values corresponding to gamma=2.2 or 1.5 from KMS
Because for that we need to program palette registers in 10.6 bit mode of hardware.
>- the KMS interface allows us to name properties independently and enumerate them. It seems like right now you can't enumerate properties or guess what "property 0" is. I'd rather set the "Color conversion matrix" than remember to set >"property 0" (and even then, I'm not really sure it exists).

All the properties are getting enumerated in color manager register function. The framework defines proper identifiers and mapping for each property, and every property is having a corresponding soft-lut to be loaded with correction values.

- you can reuse the get/set infrastructure which is already in place


>Another thing that came out of the discussion on irc is that we should standardize the properties. For example we could use a text file describing the name of the controls and the format of the data (something similar to the device tree >bindings). That way user space can expect "color conversion matrix" to mean the same thing everywhere, to get the same data as input, and to work the same way on all platforms.
If you can please have a look on the header file, we are almost doing the same thing, in form of a protocol.

Stéphane

Regards
Shashank
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