Hello Maxime,
On Tue, 14 Oct 2025 17:36:47 +0200
Maxime Ripard <mrip...@kernel.org> wrote:
> On Tue, Oct 14, 2025 at 04:32:28PM +0200, Kory Maincent wrote:
> > From: "Kory Maincent (TI.com)" <kory.mainc...@bootlin.com>
> >
> > The drm_kms_helper_poll_fini() and drm_atomic_helper_shutdown() helpers
> > should only be called when the device has been successfully registered.
> > Currently, these functions are called unconditionally in tilcdc_fini(),
> > which causes warnings during probe deferral scenarios.
> >
> > [ 7.972317] WARNING: CPU: 0 PID: 23 at
> > drivers/gpu/drm/drm_atomic_state_helper.c:175
> > drm_atomic_helper_crtc_duplicate_state+0x60/0x68 ... [ 8.005820]
> > drm_atomic_helper_crtc_duplicate_state from
> > drm_atomic_get_crtc_state+0x68/0x108 [ 8.005858]
> > drm_atomic_get_crtc_state from drm_atomic_helper_disable_all+0x90/0x1c8 [
> > 8.005885] drm_atomic_helper_disable_all from
> > drm_atomic_helper_shutdown+0x90/0x144 [ 8.005911]
> > drm_atomic_helper_shutdown from tilcdc_fini+0x68/0xf8 [tilcdc] [
> > 8.005957] tilcdc_fini [tilcdc] from tilcdc_pdev_probe+0xb0/0x6d4 [tilcdc]
> >
> > Fix this by moving both drm_kms_helper_poll_fini() and
> > drm_atomic_helper_shutdown() inside the priv->is_registered conditional
> > block, ensuring they only execute after successful device registration.
> >
> > Fixes: 3c4babae3c4a ("drm: Call drm_atomic_helper_shutdown() at
> > shutdown/remove time for misc drivers") Signed-off-by: Kory Maincent
> > (TI.com) <kory.mainc...@bootlin.com> ---
> > drivers/gpu/drm/tilcdc/tilcdc_drv.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> > b/drivers/gpu/drm/tilcdc/tilcdc_drv.c index 7caec4d38ddf..2031267a3490
> > 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> > +++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> > @@ -172,11 +172,11 @@ static void tilcdc_fini(struct drm_device *dev)
> > if (priv->crtc)
> > tilcdc_crtc_shutdown(priv->crtc);
> >
> > - if (priv->is_registered)
> > + if (priv->is_registered) {
> > drm_dev_unregister(dev);
> > -
> > - drm_kms_helper_poll_fini(dev);
> > - drm_atomic_helper_shutdown(dev);
> > + drm_kms_helper_poll_fini(dev);
> > + drm_atomic_helper_shutdown(dev);
> > + }
> > tilcdc_irq_uninstall(dev);
> > drm_mode_config_cleanup(dev);
>
> I don't think that's the right fix. tilcdc_fini is pretty complex
> because it gets called from multiple locations with various level of
> initialisation.
>
> This is done because tilcdc_init is using a bunch of deprecated
> functions with better alternatives now, and those would make the job of
> tilcdc_fini much easier.
>
> That's what we should be focusing on.
I am also currently focusing on improving this driver (which has indeed some
weird code leftover), but this work will land in drm misc next while this is a
fix for the current implementation which fix an unwanted warning.
Regards,
--
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
