Re: [PATCH v2 1/4] drm/dp: Add a way to init/add a connector in separate steps

[Maxime Ripard <mripard@kernel.org>]

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On Mon, Dec 02, 2024 at 03:24:43PM +0200, Imre Deak wrote:
> On Mon, Dec 02, 2024 at 02:07:36PM +0200, Jani Nikula wrote:
> > On Mon, 02 Dec 2024, Maxime Ripard <mripard@kernel.org> wrote:
> > > It's not about whether we have a problem or not: you introduce new
> > > framework functions, you need to have kunit tests to check their
> > > behaviour.
> > 
> > I don't fundamentally disagree with that goal, but it does seem like a
> > pretty drastic policy change. I don't recall a discussion where we made
> > that decision, nor can I find any documentation stating this. Or what
> > exactly the requirement is; it's totally unclear to me.
> > 
> > Had I been involved, I would've pointed out that while adding tests is
> > good, it inevitably increases the friction of adding new stuff to drm
> > core. It's super tempting for people to just get their jobs done. If
> > doing the right thing adds yet another hurdle, we may see more stuff
> > being added in drivers instead of drm core.
> > 
> > (Case in point, we already hacked around the problem being solved here
> > with commit d58f65df2dcb ("drm/i915/dp_mst: Fix connector initialization
> > in intel_dp_add_mst_connector()"). We could've just dropped the ball
> > right there.)
> 
> Fwiw, in this case adding tests for drm_connector_init_core() and
> drm_connector_add() looks simple enough.
> 
> IIUC it's the 3 testcases in drmm_connector_init_tests[] performed for
> drm_connector_init_core() and additional 3 test cases checking that (1)
> drm_connector_init_core() doesn't add the connector to the connector
> list, (2) drm_connector_add() adds it and (3) drm_connector_add() fails
> (by not adding the connector to the list and emitting a dmesg WARN) if
> drm_connector_init_core() was not called for the connector previously.
> For the last test I actually need to add the corresponding assert/early
> return to drm_connector_add().
> 
> If Maxim could confirm the above, I could resend the patchset adding
> these tests.

Yep, sounds great, thanks!
Maxime

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