Re: [PATCH v4 07/10] gpu: nova-core: gsp: cmdq: split the transport part of the receive path

["Alexandre Courbot" <acourbot@nvidia.com>]

On Wed Oct 14, 2026 at 12:56 PM JST, Eliot Courtney wrote:
<...>
>> -    /// Receive a message from the GSP.
>> +    /// Wait for the next element on the message queue, pass it to [`MessageElement::read`], and
>> +    /// advances the read pointer past it.
>>      ///
>> -    /// A message whose function code is `M::FUNCTION` is decoded and returned. Any other message
>> -    /// is logged as an event.
>> -    ///
>> -    /// The read pointer is always advanced past the message, regardless of whether it matched.
>> +    /// The read pointer advances regardless of whether [`MessageElement::read`] succeeds or not.
>>      ///
>>      /// # Errors
>>      ///
>> -    /// - `ETIMEDOUT` if `timeout` has elapsed before any message becomes available.
>> -    /// - `EIO` if there was some inconsistency (e.g. message shorter than advertised) on the
>> -    ///   message queue.
>> -    /// - `ENOMSG` if the message was not the awaited reply.
>> -    ///
>> -    /// Error codes returned by [`MessageFromGsp::read`] are propagated as-is.
>> -    fn receive_msg<M: MessageFromGsp>(&mut self, timeout: Delta) -> Result<M>
>> -    where
>> -        // This allows all error types, including `Infallible`, to be used for `M::InitError`.
>> -        Error: From<M::InitError>,
>> -    {
>> +    /// Errors from [`Self::wait_for_msg`] and from [`MessageElement::read`] are propagated
>> +    /// as-is.
>> +    fn consume_element<M: MessageElement>(&mut self, timeout: Delta) -> Result<M> {
>
> Ok, so we are changing the semantics to this always consumes the element
> in a few more cases. I think this is ok and it's documented so sgtm. And
> maybe we do something for poisoning later?

Yes, John had a proper poisoning mechanism in the r000 series, but I
suggested we revisit that after the r000 conversion to simplify and
introduce a generic `Poisonable` container (or something in the same
fashion as `Mutex`) instead of using a `bool`. So that's definitely on
the radar.