Re: [PATCH v3 2/2] gpu: nova-core: add boot42 support for next-gen GPUs

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

On Thu Oct 30, 2025 at 9:37 AM JST, John Hubbard wrote:
> On 10/29/25 6:54 AM, Alexandre Courbot wrote:
>> On Wed Oct 29, 2025 at 8:26 PM JST, Danilo Krummrich wrote:
>> <snip>
> ...
>> I don't think this will work because `NV_PMC_BOOT_0` and
>> `NV_PMC_BOOT_42` are different types, so we cannot alternate them in the
>> same call to `try_from`. But the following should:
>> 
>>     let boot0 = regs::NV_PMC_BOOT_0::read(bar);
>>     ...
>> 
>>     if boot0.is_nv04() {
>>         Err(ENODEV)?
>>     }
>> 
>>     if boot0.is_next_gen() {
>>         Spec::try_from(regs::NV_PMC_BOOT_42::read(bar))
>>     } else {
>>         Spec::try_from(boot0)
>>     }
>> 
>
> Done. Final code snippet looks like this:
>
>         let boot0 = regs::NV_PMC_BOOT_0::read(bar);
>
>         if boot0.use_boot42_instead() {
>             Spec::try_from(regs::NV_PMC_BOOT_42::read(bar))
>         } else {
>             Spec::try_from(boot0)
>         }

The previous code was returning `ENODEV` in case of NV04, aren't we
losing this? Or is it moved to BOOT0's `try_from`?