linux-kernel - Re: [PATCH v4] drm/tilcdc: Fix removal actions in case of failed probe

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Message-ID: <CAD=FV=WikKrpLKvaxD22H0s3XHeG=WUiRrLJ0eQMM2pqvXJhuw@mail.gmail.com>
Date: Mon, 1 Dec 2025 10:10:01 -0800
From: Doug Anderson <dianders@...omium.org>
To: Kory Maincent <kory.maincent@...tlin.com>
Cc: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>, Maxime Ripard <mripard@...nel.org>, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	Bajjuri Praneeth <praneeth@...com>, Luca Ceresoli <luca.ceresoli@...tlin.com>, 
	Louis Chauvet <louis.chauvet@...tlin.com>, stable@...r.kernel.org, 
	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 v4] drm/tilcdc: Fix removal actions in case of failed probe

Hi,

On Tue, Nov 25, 2025 at 1:06 AM Kory Maincent <kory.maincent@...tlin.com> 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 rewriting the failed probe cleanup path using the standard
> goto error handling pattern, which ensures that cleanup functions are
> only called on successfully initialized resources. Additionally, remove
> the now-unnecessary is_registered flag.
>
> Cc: stable@...r.kernel.org
> 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'm working on removing the usage of deprecated functions as well as
> general improvements to this driver, but it will take some time so for
> now this is a simple fix to a functional bug.
>
> Change in v4:
> - Fix an unused label warning reported by the kernel test robot.
>
> Change in v3:
> - Rewrite the failed probe clean up path using goto
> - Remove the is_registered flag
>
> Change in v2:
> - Add missing cc: stable tag
> - Add Swamil reviewed-by
> ---
>  drivers/gpu/drm/tilcdc/tilcdc_crtc.c |  2 +-
>  drivers/gpu/drm/tilcdc/tilcdc_drv.c  | 53 ++++++++++++++++++----------
>  drivers/gpu/drm/tilcdc/tilcdc_drv.h  |  2 +-
>  3 files changed, 37 insertions(+), 20 deletions(-)

Seems reasonable to me. I did a once-over and based on code inspection
it looks like things are being reversed properly. I agree this should
probably land to fix the regression while waiting for a bigger
cleanup.

Reviewed-by: Douglas Anderson <dianders@...omium.org>

This fixup has been sitting out there for a while. Who is the right
person to apply it? If nobody else does and there are no objections, I
can apply it to "fixes" next week...

-Doug