On Tue Sep 1, 2026 at 9:07 AM CEST, Alistair Popple wrote: > On 2026-09-01 at 06:42 +1000, Gary Guo <[email protected]> wrote... >> On Mon Aug 31, 2026 at 9:08 PM BST, Danilo Krummrich wrote: >> > On Fri Aug 28, 2026 at 5:35 AM CEST, Alistair Popple wrote: >> >> +/// API handle for the auxiliary bus child drivers to interact with >> >> nova-core. >> >> +pub struct NovaCoreApi<'bound> { >> >> + #[expect(unused)] >> >> + pub(crate) gpu: Pin<&'bound Gpu<'bound>>, >> >> +} >> >> + >> >> +impl NovaCoreApi<'_> { >> >> + /// Obtain a [`NovaCoreApi`] handle from an auxiliary device >> >> registered >> >> + /// by nova-core. >> >> + pub fn of(adev: &auxiliary::Device<Bound>) -> >> >> Result<Pin<&NovaCoreApi<'_>>> { >> >> + adev.registration_data::<CovariantForLt!(NovaCoreApi<'_>)>() >> >> + } >> >> +} >> > >> > CovariantForLt does not hold anymore on latest drm-rust-next, as Cmdq has a >> > Mutex. So, this needs ForLt now and therefore the approach that I shared >> > in [1] >> > a while ago. I applied the changes in [2] to fix it up. > > I can see why the mutex means covariance no longer holds, but I would kind > of also expect it to not compile given it surely can't be safe here to treat > an invariant type as covariant. Is this just a limitation of the current > CovariantForLt implementation not being able to prove covariance or am I > missing > something else? Thanks.
Well, it did not compile (as expected) on my end, which is how I caught it. What's your base revision?
