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

[Marek Olšák]

We're going to do this in Mesa instead:
https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22771

Marek

On Fri, Apr 28, 2023 at 6:36 PM Marek Olšák <maraeo at gmail.com> wrote:

> On Fri, Apr 28, 2023, 16:14 Joshua Ashton <joshua at froggi.es> wrote:
>
>> 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.
>>
>
> Raphael and Mendocino have worse power consumption with retiled
> displayable DCC and modifiers, and that can also be due to how retiling is
> implemented for modifiers.
>
> Marek
>
>
>> - 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
>> >
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/amd-gfx/attachments/20230502/f26f5521/attachment.htm>