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

[John Hubbard <jhubbard@nvidia.com>]

On 11/6/26 5:38 PM, Danilo Krummrich wrote:
> 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.

This sounds right and proper, yes. :)


thanks,
-- 
John Hubbard