Hi,
On Fri, Sep 1, 2023 at 4:42 PM Douglas Anderson <dianders@xxxxxxxxxxxx> 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@xxxxxxxxxx>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
> This commit is only compile-time tested.
>
> drivers/gpu/drm/imx/ipuv3/imx-drm-core.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c b/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
> index 4a866ac60fff..4c8bc49758a7 100644
> --- a/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
> +++ b/drivers/gpu/drm/imx/ipuv3/imx-drm-core.c
> @@ -257,6 +257,7 @@ static int imx_drm_bind(struct device *dev)
> drm_kms_helper_poll_fini(drm);
> component_unbind_all(drm->dev, drm);
> err_kms:
> + dev_set_drvdata(dev, NULL);
> drm_dev_put(drm);
>
> return ret;
> @@ -269,6 +270,7 @@ static void imx_drm_unbind(struct device *dev)
> drm_dev_unregister(drm);
>
> drm_kms_helper_poll_fini(drm);
> + drm_atomic_helper_shutdown(drm);
>
> component_unbind_all(drm->dev, drm);
>
> @@ -298,6 +300,14 @@ static int imx_drm_platform_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static void imx_drm_platform_shutdown(struct platform_device *pdev)
> +{
> + struct drm_device *drm = platform_get_drvdata(pdev);
> +
> + if (drm)
> + drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
Since this is now landing through the drm-misc-next tree, I got rid of
the check for NULL when applying and landed this after the patch
("drm/atomic-helper: drm_atomic_helper_shutdown(NULL) should be a
noop").
> @@ -325,6 +335,7 @@ MODULE_DEVICE_TABLE(of, imx_drm_dt_ids);
> static struct platform_driver imx_drm_pdrv = {
> .probe = imx_drm_platform_probe,
> .remove = imx_drm_platform_remove,
> + .shutdown = imx_drm_platform_shutdown,
There was a trivial context conflict with commit 3095f1122203
("drm/imx/ipuv3: Convert to platform remove callback returning void")
that I resolved while applying.
I've now pushed to drm-misc-next:
02680d71dea8 drm/imx/ipuv3: Call drm_atomic_helper_shutdown() at
shutdown/unbind time
