[Mesa-dev] 10-bit Mesa/Gallium support

[Ilia Mirkin]

On Thu, Nov 23, 2017 at 12:55 PM, Michel Dänzer <michel at daenzer.net> wrote:
> On 2017-11-23 06:45 PM, Ilia Mirkin wrote:
>> On Thu, Nov 23, 2017 at 12:35 PM, Marek Olšák <maraeo at gmail.com> wrote:
>>> Hi everybody,
>>>
>>> Mario, feel free to push your patches if you haven't yet. (except the
>>> workaround)
>>>
>>> For AMD, I applied Mario's patches (except Wayland - that didn't
>>> apply) and added initial Gallium support:
>>> https://cgit.freedesktop.org/~mareko/mesa/log/?h=10bit
>>>
>>> What's the status of Glamor?
>>>
>>> Do we have patches for xf86-video-amdgpu? The closed should have
>>> 10-bit support, meaning we should have DDX patches already somewhere,
>>> right?
>>
>> I'd like to test this out with nouveau as well... do I understand
>> correctly that I shouldn't need anything special to check if it
>> basically works? i.e. I apply the patches, start Xorg in bpp=30 mode,
>
> First you'd need to add support for depth 30 to the Xorg driver you're
> using.

Right. That should be easy - either it's already there, or it should
be trivial to add. [Yeah, famous last words.] At least the drm driver
supports 30bpp fb's, so that's a start.

>
>
>> and then if glxgears works then I'm done? Is there a good way that I'm
>> really in 30bpp mode as far as all the software is concerned?
>
> xdpyinfo or glxinfo should work for that.

OK, so I'm looking at the output in my regular bgrx8888 mode:

  depth of root window:    24 planes
  default visual id:  0x21
  visual:
    visual id:    0x21
    class:    TrueColor
    depth:    24 planes
    available colormap entries:    256 per subfield
    red, green, blue masks:    0xff0000, 0xff00, 0xff
    significant bits in color specification:    8 bits

And presumably that would all say 30? And then in glxinfo the visual
depth would also become 30?

>
>
>> If used with a 24bpp display, is the hw supposed to dither somehow?
>
> We don't know how your hardware works. :)

I was hoping there was a common answer to that question. But I suppose
you're right. And we use a 256-sized LUT which is going to mess this
up bigtime... the later hardware does support larger ones... maybe.

Thanks,

  -ilia