drm/amd/display: disable display DCC with retiling due to worse power consumption

[Joshua Ashton]

I mean I would also like power and perf numbers for Vangogh given you
referenced 10.3.

Generic "power consumption is better" isn't enough to convince me that this
is the right call.

- Joshie 🐸✨

On Friday, 28 April 2023, Marek Olšák <maraeo at gmail.com> wrote:
> I thought the same thing initially, but then realized that's not how
modifiers were designed to work.
> Mesa should expose all modifiers it wants to allow for 3D and it doesn't
care which ones are displayable.
> The kernel should expose all modifiers it wants to allow for display.
> With that, Mesa can still use theoretically displayable DCC, but it will
only be used for anything that's not the display.
> We can, of course, disable it in Mesa instead to get the same effect.
> We would need perf numbers for dGPUs to be able to tell whether it's
beneficial with the cost of DCC retiling.
> Marek
>
> On Fri, Apr 28, 2023, 12:11 Joshua Ashton <joshua at froggi.es> wrote:
>>
>> I really don't think the kernel isn't the right place to do this.
>> Is there any reason to not just disable it from the Mesa side?
>>
>> We can already disable displayable DCC there, so I don't see why you are
even touching the kernel.
>> It makes it infinitely harder for anyone to evaluate perf and power
tradeoffs if you disable it at this level.
>>
>> The whole power vs perf trade is also not a big deal on dGPUs compared
to APUs. Probably needs a better heuristic either way to avoid regressing
perf.
>>
>> - Joshie 🐸✨
>>
>> On 28 April 2023 10:47:17 BST, "Marek Olšák" <maraeo at gmail.com> wrote:
>>>
>>> Hi,
>>> It's attached for review.
>>>
>>> Thanks,
>>> Marek
>
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