2020-05-28 08:40:50

by Krishna Manikandan

Subject: [v1] drm/msm: add shutdown support for display platform_driver

Define shutdown callback for display drm driver,
so as to disable all the CRTCS when shutdown
notification is received by the driver.

Signed-off-by: Krishna Manikandan <[email protected]>
---
drivers/gpu/drm/msm/msm_drv.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index e4b750b..7a8953f 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -1322,6 +1322,18 @@ static int msm_pdev_remove(struct platform_device *pdev)
return 0;
}

+static void msm_pdev_shutdown(struct platform_device *pdev)
+{
+ struct drm_device *drm = platform_get_drvdata(pdev);
+
+ if (!drm) {
+ DRM_ERROR("Invalid drm device node\n");
+ return;
+ }
+
+ drm_atomic_helper_shutdown(drm);
+}
+
static const struct of_device_id dt_match[] = {
{ .compatible = "qcom,mdp4", .data = (void *)KMS_MDP4 },
{ .compatible = "qcom,mdss", .data = (void *)KMS_MDP5 },
@@ -1334,6 +1346,7 @@ static int msm_pdev_remove(struct platform_device *pdev)
static struct platform_driver msm_platform_driver = {
.probe = msm_pdev_probe,
.remove = msm_pdev_remove,
+ .shutdown = msm_pdev_shutdown,
.driver = {
.name = "msm",
.of_match_table = dt_match,
--
1.9.1

2020-05-28 09:00:59

by Sai Prakash Ranjan

Subject: Re: [v1] drm/msm: add shutdown support for display platform_driver

Hi Krishna,

On 2020-05-28 14:08, Krishna Manikandan wrote:
> Define shutdown callback for display drm driver,
> so as to disable all the CRTCS when shutdown
> notification is received by the driver.
>

Would be nice to add some more context for adding this shutdown callback
something like below:

If the hardware is still accessing memory after SMMU translation is
disabled
as part of smmu shutdown callback, then the IOVAs(I/O virtual address)
which
it was using will go on the bus as the physical addresses which will
result
in unknown crashes (NoC/interconnect errors on QCOM SoCs).

PS: Credits for description: Robin Murphy

Thanks,
Sai

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation

2020-05-28 22:22:52

by Stephen Boyd

Subject: Re: [v1] drm/msm: add shutdown support for display platform_driver

Quoting Krishna Manikandan (2020-05-28 01:38:23)
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index e4b750b..7a8953f 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -1322,6 +1322,18 @@ static int msm_pdev_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static void msm_pdev_shutdown(struct platform_device *pdev)
> +{
> + struct drm_device *drm = platform_get_drvdata(pdev);
> +
> + if (!drm) {
> + DRM_ERROR("Invalid drm device node\n");
> + return;
> + }

When would this ever happen? Please drop this useless check.

> +
> + drm_atomic_helper_shutdown(drm);
> +}
> +
> static const struct of_device_id dt_match[] = {
> { .compatible = "qcom,mdp4", .data = (void *)KMS_MDP4 },
> { .compatible = "qcom,mdss", .data = (void *)KMS_MDP5 },