[bug report] drm/vkms: Allow to configure multiple CRTCs

[José Expósito]

Hi Dan,

On Fri, Aug 08, 2025 at 05:01:35PM +0300, Dan Carpenter wrote:
> On Fri, Aug 08, 2025 at 01:15:03PM +0200, José Expósito wrote:
> > > drivers/gpu/drm/vkms/tests/vkms_config_test.c
> > >     231 static void vkms_config_test_get_crtcs(struct kunit *test)
> > >     232 {
> > >     233         struct vkms_config *config;
> > >     234         struct vkms_config_crtc *crtc_cfg;
> > >     235         struct vkms_config_crtc *crtc_cfg1, *crtc_cfg2;
> > >     236 
> > >     237         config = vkms_config_create("test");
> > >     238         KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
> > >     239 
> > >     240         KUNIT_ASSERT_EQ(test, vkms_config_get_num_crtcs(config), 0);
> > >     241         vkms_config_for_each_crtc(config, crtc_cfg)
> > >     242                 KUNIT_FAIL(test, "Unexpected CRTC");
> > >     243 
> > >     244         crtc_cfg1 = vkms_config_create_crtc(config);
> > >                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > > This file has no error checking.
> > > 
> > > I didn't send an email about it at first because this is just test code so
> > > who cares, but I was recently burned by ignoring errors so now I'm going
> > > through a bunch of old warnings to say that, "Hey, if the author ignores the
> > > error checking that's fine, but I'm in the clear."
> > > 
> > >     245         KUNIT_ASSERT_EQ(test, vkms_config_get_num_crtcs(config), 1);
> > 
> > While the "crtc_cfg1" pointer is not checked, we check that the	number 
> > of CRTCs matches the expected value and...
> > 
> 
> Ah yes.  That does work...  Sorry for the noise.

No noise at all, there were other places were the check made sense.

I sent a patch fixing them:
https://lore.kernel.org/dri-devel/20250811101529.150716-1-jose.exposito89@gmail.com/T/#u

Thanks a lot for reporting this issue!!
Jose

> 
> regards,
> dan carpenter
>