Hi Jerry, Harry, On Fri, 14 Aug 2026 at 16:41, Zuo, Jerry <[email protected]> wrote: \> > I really think the burden of proof for implicit semantics in KMS should be the > > other way around: do we unavoidably need this, or is there (currently) no > > other option at all? > > > > I don't think ALLM falls into this basket at all. It's nice to have for > > gaming (and > > mandatory for gaming VRR mode), but there are plenty of different scenarios > > where having it on or off is a legitimate choice. For instance, should > > desktops > > imply ALLM because they aren't going to smooth your text into oblivion, or > > should they not because you're probably not going to read text on a 49" > > display? Should all games imply ALLM because you need the response time, > > or are you maybe playing Myst on your TV? > > > > I understand the attraction behind 'we can just stuff this in the kernel > > and it > > will dtrt', but hey, that's what people thought about Broadcast RGB at the > > time. Or colour model/subsampling selection on the wire. Or or or ... > > Yes I agreed. content_type -> ALLM doesn't clear that bar, and I'll drop it. > > I'll submit another v4 based on below soon: > 1. Keep only the case we have no choice about: set ALLM_Mode=1 when > Gaming-VRR is active (VRR_EN=1) and the sink advertises ALLM, per spec > 7.6.6. > This stays in the driver. > 2. Remove the content_type == Game heuristic from both the modeset and the > freesync paths. No implicit ALLM derived from content type. > 3. No new implicit semantics, and no DRM-helper "default" either. If a > concrete need for explicit ALLM control shows up, it should be a proper > (ideally generic) property with a real userspace user driving it, not > something the kernel infers.
Here's a Weston MR which provides the same user-facing API. There is per-output configuration for ALLM being always enabled, always disabled, or enabled only when a game is present on screen: https://gitlab.freedesktop.org/wayland/weston/-/merge_requests/2189 Would you be able to re-send this series with a binary ALLM mode and linking to this Weston MR? Cheers, Daniel
