Re: linux-next: build failure after merge of the rust tree

Alice Ryhl
2025-11-17T14:51:07Z

On Mon, Nov 17, 2025 at 07:04:17PM +1100, Stephen Rothwell wrote:
> Hi all,
>
> After merging the rust tree, today's linux-next build (x86_64
> allmodconfig) failed like this:
>
> error[E0277]: `Chipset` doesn't implement `core::fmt::Display`
> --> drivers/gpu/nova-core/gpu.rs:233:13
> |
> 233 | self.chipset,
> | ^^^^^^^^^^^^ `Chipset` cannot be formatted with the default formatter
> |
> = help: the trait `core::fmt::Display` is not implemented for `Chipset`
> = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
> = note: this error originates in the macro `$crate::format_args` which comes from the expansion of the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
>
> error[E0277]: `Revision` doesn't implement `core::fmt::Display`
> --> drivers/gpu/nova-core/gpu.rs:235:13
> |
> 235 | self.revision
> | ^^^^^^^^^^^^^ `Revision` cannot be formatted with the default formatter
> |
> = help: the trait `core::fmt::Display` is not implemented for `Revision`
> = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
> = note: this error originates in the macro `$crate::format_args` which comes from the expansion of the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
>
> error[E0277]: the trait bound `MsgFunction: kernel::fmt::Display` is not satisfied
> --> drivers/gpu/nova-core/gsp/cmdq.rs:532:9
> |
> 532 | / dev_dbg!(
> 533 | | &self.dev,
> 534 | | "GSP RPC: send: seq# {}, function={}, length=0x{:x}\n",
> | | -- required by a bound introduced by this call
> 535 | | self.seq,
> 536 | | M::FUNCTION,
> 537 | | dst.header.length(),
> 538 | | );
> | |_________^ the trait `kernel::fmt::Display` is not implemented for `MsgFunction`
> |
> = help: the following other types implement trait `kernel::fmt::Display`:
> &T
> Arc<T>
> Arguments<'_>
> BStr
> Box<T, A>
> CStr
> Chipset
> Class
> and 22 others
> = note: required for `kernel::fmt::Adapter<&MsgFunction>` to implement `core::fmt::Display`
> note: required by a bound in `core::fmt::rt::Argument::<'_>::new_display`
> --> /usr/lib/rustlib/src/rust/library/core/src/fmt/rt.rs:113:27
> |
> 113 | pub fn new_display<T: Display>(x: &T) -> Argument<'_> {
> | ^^^^^^^ required by this bound in `Argument::<'_>::new_display`
> = note: this error originates in the macro `::core::format_args` which comes from the expansion of the macro `dev_dbg` (in Nightly builds, run with -Z macro-backtrace for more info)
>
> error: aborting due to 3 previous errors
>
> For more information about this error, try `rustc --explain E0277`.
>
> Caused by commit
>
> c5cf01ba8dfe ("rust: support formatting of foreign types")
>
> (I think) interacting with commits
>
> 38b7cc448a5b ("gpu: nova-core: implement Display for Spec")
> 75f6b1de8133 ("gpu: nova-core: gsp: Add GSP command queue bindings and handling")
>
> from the drm-rust tree.

I applied a patch to drm-rust-next that makes this error go away.

Alice