[PATCH xserver] xfree86: fix gamma compute when palette_size > 256

[Yu, Qiang]

>> Or maybe it's better to enlarge the crtc gamma size according to randr crtc
>> and let kernel driver to do the resize fit.
>
> Yes, that needs to happen anyway to make the display hardware actually
> take advantage of 30 bits per pixel, doesn't it?
But for randr crtc gamma size < 256, I see you don't shrink the crtc gamma
size. Any reason?


>> But I see driver like amdgpu with old KMS driver only has 256 entries and the
>> gamma set syscall won't work correctly for size>256.
>
> That needs to be fixed then, and the userspace driver should probably
> only allow setting depth 30 when it knows the kernel driver can handle it.
That's the DDX work. For amdgpu, seems we can support it in DC KMS.

Regards,
Qiang