Nouveau - Sep 2025 - [PATCH v3 02/11] gpu: nova-core: move GSP boot code out of `Gpu` constructor

On Wed Sep 3, 2025 at 9:10 AM CEST, Alexandre Courbot
wrote:
> On Wed Sep 3, 2025 at 8:12 AM JST, Danilo Krummrich wrote:
>> On 9/2/25 4:31 PM, Alexandre Courbot wrote:
>>>       pub(crate) fn new(
>>>           pdev: &pci::Device<device::Bound>,
>>>           devres_bar: Arc<Devres<Bar0>>,
>>
>> The diff is hiding it, but with this patch we should also make sure
that this
>> returns impl PinInit<Self, Error> rather than Result<impl
PinInit<Self>.
>>
>> I think this should be possible now.
>
> There is still code that can return errors (falcon creation, etc) - do
> you mean that we should move it into the pin initializer and turn it
> into a `try_pin_init`?
Yeah, that would be better practice, if it doesn't work out for a good
reason
we can also fall back to Result<impl PinInit<Self, Error>, but we
should at
least try to avoid it.

On Wed Sep 3, 2025 at 5:27 PM JST, Danilo Krummrich
wrote:
> On Wed Sep 3, 2025 at 9:10 AM CEST, Alexandre Courbot wrote:
>> On Wed Sep 3, 2025 at 8:12 AM JST, Danilo Krummrich wrote:
>>> On 9/2/25 4:31 PM, Alexandre Courbot wrote:
>>>>       pub(crate) fn new(
>>>>           pdev: &pci::Device<device::Bound>,
>>>>           devres_bar: Arc<Devres<Bar0>>,
>>>
>>> The diff is hiding it, but with this patch we should also make sure
that this
>>> returns impl PinInit<Self, Error> rather than Result<impl
PinInit<Self>.
>>>
>>> I think this should be possible now.
>>
>> There is still code that can return errors (falcon creation, etc) - do
>> you mean that we should move it into the pin initializer and turn it
>> into a `try_pin_init`?
>
> Yeah, that would be better practice, if it doesn't work out for a good
reason
> we can also fall back to Result<impl PinInit<Self, Error>, but we
should at
> least try to avoid it.
I tried but could not do it in a way that is satisfying. The problem is
that `Gpu::new` receives a `Arc<Devres<Bar0>>`, which we need to
`access` in order to do anything useful with it. If we first store it
into the `Gpu` structure, then every subsequent member needs to `access`
it in its own code block in order to perform their own initialization.
This is quite cumbersome.

If there is a way to obtain the `Bar0` once after the `bar` member of
`Gpu` is initialized, and then use that instance with each remaining
member, then that problem would go away but I am not aware of such a
thing.