[PATCH i-g-t 0/3] lib/kunit: Support writable filter* parameters of kunit module

[Lucas De Marchi]

On Fri, Jan 26, 2024 at 02:14:34PM +0100, Janusz Krzysztofik wrote:
>Hi Lucas,
>
>Thanks for looking at this.
>
>On Thursday, 25 January 2024 18:25:55 CET Lucas De Marchi wrote:
>> On Thu, Jan 25, 2024 at 05:52:09PM +0100, Janusz Krzysztofik wrote:
>> >Instead of wasting resources on reloading the base Kunit module each time
>> >a different set of filter parameters is needed, try to write the required
>> >values to sysfs representation of those parameters.  If that fails (e.g.
>> >on older LTS kernels with read-only filter parameters), fall back to
>>
>> we can't really execute anything on LTS kernel.
>
>Yes, we can, and we do, since modules of DRM generic selftests like drm_buddy
>or drm_mm and a couple of KMS related ones were converted from i915 selftest
>format to KUnit and our IGT counterparts that load those modules and execute
>those tests were updated accordingly.  Maybe our CI no longer exercises IGT
>tests on LTS kernels, but the community may still do, I believe.

there's very little benefit on that IMO as these are tightly coupled to the
kernel side.  Distros don't even ship kunit enabled so people would have
to build an lts kernel for that.

The way this compatibility is coded intermixed makes it
much harder to get it right.  I'd rather just add simple skips or add a
compat layer that takes a totally different path if compat is desired.

Lucas De Marchi

>
>Thanks,
>Janusz
>
>
>> I don't think think it's
>> worth keeping the multiple fallbacks we have now.
>>
>> I think trying to maintain compat is good, but I'm not sure it makes
>> sense for these tightly coupled tests with the kernel.
>>
>> Lucas De Marchi
>>
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