On Wed, 21 Oct 2020 at 17:34, Daniel Vetter daniel@ffwll.ch wrote:
On Wed, Oct 21, 2020 at 05:11:00PM +0100, Daniel Stone wrote:
It makes sense to me: some modes are annotated with a 'low-power' flag, tucked away behind a client cap which makes clients opt in, and they can switch into the low-power mode (letting the display/panel save a lot of power) _if_ they only have at most 15% of pixels lit up.
My worry is about the 15% though ... what happens when hardware allows up to 20%, or only allows 10%?
Yeah exactly, that's what I'm worried about too, these kind of details. Opt-in flag for special modes, no problem, but we need to make sure we agree on what flavour of special exactly they are.
If we can reuse the same modelines, then rather than create new modelines just for low-power modes, I'd rather create a client CRTC property specifying the number/percentages of pixels on the CRTC which are lit non-zero. That would give us more wriggle room to change the semantics, as well as redefine 'low power' in terms of monochrome/scaled/non-bright/etc modes. But it does make the switching-between-clients problem even worse than it already is.
Yeah, that would make sense too. Or maybe even add read-only hint that says "if you're below 15% non-black we can do low power for your, please be nice".
If the hardware can actually do that autonomously then great, but I'm guessing the reason we're talking about separate opt-in modes here is that it can't.
Cheers, Daniel