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    SubjectRe: [RFT PATCH 13/15] drm/imx/ipuv3: Call drm_atomic_helper_shutdown() at shutdown/unbind time
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    Hi,

    On Di, 2023-09-05 at 13:29 -0700, Doug Anderson wrote:
    > Hi,
    >
    > On Mon, Sep 4, 2023 at 1:30 AM Philipp Zabel <p.zabel@pengutronix.de> wrote:
    > >
    > > On Fr, 2023-09-01 at 16:41 -0700, Douglas Anderson wrote:
    > > > Based on grepping through the source code this driver appears to be
    > > > missing a call to drm_atomic_helper_shutdown() at system shutdown time
    > > > and at driver unbind time. Among other things, this means that if a
    > > > panel is in use that it won't be cleanly powered off at system
    > > > shutdown time.
    > > >
    > > > The fact that we should call drm_atomic_helper_shutdown() in the case
    > > > of OS shutdown/restart and at driver remove (or unbind) time comes
    > > > straight out of the kernel doc "driver instance overview" in
    > > > drm_drv.c.
    > > >
    > > > A few notes about this fix:
    > > > - When adding drm_atomic_helper_shutdown() to the unbind path, I added
    > > > it after drm_kms_helper_poll_fini() since that's when other drivers
    > > > seemed to have it.
    > > > - Technically with a previous patch, ("drm/atomic-helper:
    > > > drm_atomic_helper_shutdown(NULL) should be a noop"), we don't
    > > > actually need to check to see if our "drm" pointer is NULL before
    > > > calling drm_atomic_helper_shutdown(). We'll leave the "if" test in,
    > > > though, so that this patch can land without any dependencies. It
    > > > could potentially be removed later.
    > > > - This patch also makes sure to set the drvdata to NULL in the case of
    > > > bind errors to make sure that shutdown can't access freed data.
    > > >
    > > > Suggested-by: Maxime Ripard <mripard@kernel.org>
    > > > Signed-off-by: Douglas Anderson <dianders@chromium.org>
    > >
    > > Thank you,
    > > Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
    >
    > Thanks! I notice that:
    >
    > ./scripts/get_maintainer.pl --scm -f drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
    >
    > Doesn't say drm-misc but also when I look at the MAINTAINERS file and
    > find the section for "DRM DRIVERS FOR FREESCALE IMX"

    That should probably say "IMX5/6" nowadays. There are a lot more i.MX
    that do not use IPUv3 than those that do.

    > it doesn't explicitly list a different git tree.

    I used to send pull requests from git.pengutronix.de/git/pza/linux,
    same as for the reset controller framework. I might still have to do
    that for changes in drivers/gpu/ipu-v3 that need coordination between
    drm and v4l2, but usually pure drm/imx/ipuv3 changes are pushed to drm-
    misc.

    > I guess the "shawnguo" git tree listed by get_maintainer.pl is just
    > from regex matching?

    The "N: imx" pattern in "ARM/FREESCALE IMX / MXC ARM ARCHITECTURE", I
    think.

    > Would you expect this to go through drm-misc? If so, I'll probably
    > land it sooner rather than later. I can also post up a patch making it
    > obvious that "DRM DRIVERS FOR FREESCALE IMX" goes through drm-misc if
    > you don't object.

    Yes, both would be great.

    regards
    Philipp

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