On 21.09.2023 21:26, 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@xxxxxxxxxx>
> Reviewed-by: Maxime Ripard <mripard@xxxxxxxxxx>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Seems to be working fine on all my test Exynos-based boards with display.
Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Reviewed-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> ---
> This commit is only compile-time tested.
>
> (no changes since v1)
>
> drivers/gpu/drm/exynos/exynos_drm_drv.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c
> index 8399256cb5c9..5380fb6c55ae 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
> @@ -300,6 +300,7 @@ static int exynos_drm_bind(struct device *dev)
> drm_mode_config_cleanup(drm);
> exynos_drm_cleanup_dma(drm);
> kfree(private);
> + dev_set_drvdata(dev, NULL);
> err_free_drm:
> drm_dev_put(drm);
>
> @@ -313,6 +314,7 @@ static void exynos_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);
> drm_mode_config_cleanup(drm);
> @@ -350,9 +352,18 @@ static int exynos_drm_platform_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static void exynos_drm_platform_shutdown(struct platform_device *pdev)
> +{
> + struct drm_device *drm = platform_get_drvdata(pdev);
> +
> + if (drm)
> + drm_atomic_helper_shutdown(drm);
> +}
> +
> static struct platform_driver exynos_drm_platform_driver = {
> .probe = exynos_drm_platform_probe,
> .remove = exynos_drm_platform_remove,
> + .shutdown = exynos_drm_platform_shutdown,
> .driver = {
> .name = "exynos-drm",
> .pm = &exynos_drm_pm_ops,
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
