Re: [PATCH v6 0/3] gpu: nova-core: retain the GSP-RM log buffers

["Danilo Krummrich" <dakr@kernel.org>]

On Sat Nov 7, 2026 at 1:39 AM CET, John Hubbard wrote:
> Specifically, (as you mention above), I had to add "retained/" to the
> directory path in order to retrieve the logs. That is awkward, because
> that means that if I ask for gsp_keep_logs=1, now I have to know/remember
> that they are in:
>
>     /sys/kernel/debug/nova-core/retained/<BDF>/
>
> instead of:
>
>     /sys/kernel/debug/nova-core/<BDF>
>
> We should try hard to avoid such complications, especially given that
> debugging is often done when one has a thousand other complicated things
> going on at the same time, late at night, too.

It doesn't bother me too much, but I think the concern is fair.

The retained directory keeps a clear separation between live buffers and
retained buffers, but I don't think that's a strong reason to keep it.

In nouveau we don't have that separation either, but nouveau also keeps the
retained buffers until module unload. I.e. after the first retention nouveau
never exposes new buffers (including the live ones) unless you reload the
module. This works, but can be rather unexpected when e.g. doing multiple
rebinds via sysfs.

Rebinding via sysfs can be especially useful in multi-GPU setups, where you
don't want to unbind all GPUs by unloading the module.

So, getting rid of retained/ is fine, but let's not follow what nouveau does.
Instead, let's make the same files point to the live buffers when the device is
bound and otherwise let them point at the retained buffers.

Thanks,
Danilo