linux-kernel - Re: [PATCH] drm/tilcdc: Fix removal actions in case of failed probe

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Message-ID: <7a158fa1-9a82-444c-a198-d90bf1ebf1fb@ti.com>
Date: Wed, 15 Oct 2025 10:30:13 +0530
From: Swamil Jain <s-jain1@...com>
To: Kory Maincent <kory.maincent@...tlin.com>,
        Tomi Valkeinen
	<tomi.valkeinen@...asonboard.com>,
        Douglas Anderson <dianders@...omium.org>,
        Maxime Ripard <mripard@...nel.org>, <dri-devel@...ts.freedesktop.org>,
        <linux-kernel@...r.kernel.org>
CC: Bajjuri Praneeth <praneeth@...com>,
        Louis Chauvet
	<louis.chauvet@...tlin.com>,
        <thomas.petazzoni@...tlin.com>, Jyri Sarha
	<jyri.sarha@....fi>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Subject: Re: [PATCH] drm/tilcdc: Fix removal actions in case of failed probe

Hi Köry,
Thanks for the patch.

On 14-10-2025 20:02, Kory Maincent wrote:
> From: "Kory Maincent (TI.com)" <kory.maincent@...tlin.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.maincent@...tlin.com>
> ---

I would suggest the same, as Maxime mentioned to improve the driver to 
replace the deprecated functions with better alternatives. But as you 
mentioned, you are working on improving the driver and for now to remove 
unwanted warnings it is good to have this patch in drm misc next.

Reviewed-by: Swamil Jain <s-jain1@...com>

---
Regards,
Swamil>   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);
>