imx_ldb: lockdep warning on 5.14.x

[Fabio Estevam]

On Sun, Oct 10, 2021 at 12:39 PM Fabio Estevam <festevam at gmail.com> wrote:
>
> Hi,
>
> I am getting the lockdep warning below on a imx6q-sabred running 5.14.9.
>
> Haven't debugged this yet, but just wanted to report in case someone
> has any suggestions.

git bisect shows that the guilty commit is:

commit f4b34faa08428d813fc3629f882c503487f94a12
Author: Daniel Vetter <daniel.vetter at ffwll.ch>
Date:   Thu Jan 21 16:29:55 2021 +0100

    drm/imx: Annotate dma-fence critical section in commit path

    drm_atomic_helper_commit_hw_done() is the last thing (no plane cleanup
    apparrently), so it's the entire function. And a nice comment
    explaining why the wait_for_flip_done is ahead, unlike the usual
    sequence.

    Aside, I think since the atomic helpers do track plane disabling now
    separately this might no longer be a real problem since:

    commit 21a01abbe32a3cbeb903378a24e504bfd9fe0648
    Author: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
    Date:   Mon Sep 4 12:48:37 2017 +0200

        drm/atomic: Fix freeing connector/plane state too early by
tracking commits, v3.

    Plus the subsequent bugfixes of course, this was tricky to get right.

    Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
    Cc: Philipp Zabel <p.zabel at pengutronix.de>
    Cc: Shawn Guo <shawnguo at kernel.org>
    Cc: Sascha Hauer <s.hauer at pengutronix.de>
    Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
    Cc: Fabio Estevam <festevam at gmail.com>
    Cc: NXP Linux Team <linux-imx at nxp.com>
    Cc: linux-arm-kernel at lists.infradead.org
    Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>

If I revert this commit on top of 5.14, the lockdep warning is gone.

Daniel,

How do we fix this?

Thanks