diff mbox series

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

Message ID 20230901164111.RFT.13.I0a9940ff6f387d6acf4e71d8c7dbaff8c42e3aaa@changeid (mailing list archive)
State New, archived
Headers show
Series drm: non-drm-misc drivers call drm_atomic_helper_shutdown() at the right times | expand

Commit Message

Doug Anderson Sept. 1, 2023, 11:41 p.m. UTC
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>
---
This commit is only compile-time tested.

 drivers/gpu/drm/imx/ipuv3/imx-drm-core.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Comments

Maxime Ripard Sept. 4, 2023, 7:55 a.m. UTC | #1
On Fri, 1 Sep 2023 16:41:24 -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.
> 
> [ ... ]

Reviewed-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime
Philipp Zabel Sept. 4, 2023, 8:30 a.m. UTC | #2
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>

regards
Philipp
Doug Anderson Sept. 5, 2023, 8:29 p.m. UTC | #3
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" it doesn't
explicitly list a different git tree. I guess the "shawnguo" git tree
listed by get_maintainer.pl is just from regex matching?

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.

Thanks!

-Doug
Philipp Zabel Sept. 6, 2023, 5:47 a.m. UTC | #4
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
Doug Anderson Sept. 6, 2023, 2:30 p.m. UTC | #5
Hi,

On Tue, Sep 5, 2023 at 10:47 PM Philipp Zabel <p.zabel@pengutronix.de> wrote:
>
> 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.

Maintainers update posted at:

https://lore.kernel.org/r/20230906072803.1.Idef7e77e8961cbeb8625183eec9db0356b2eccd0@changeid

I'll aim to land ${SUBJECT} patch early next week unless there are any
objections.

-Doug
Doug Anderson Sept. 13, 2023, 6:21 p.m. UTC | #6
Hi,

On Fri, Sep 1, 2023 at 4:42 PM Douglas Anderson <dianders@chromium.org> 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>
> ---
> 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
diff mbox series

Patch

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));
+}
+
 #ifdef CONFIG_PM_SLEEP
 static int imx_drm_suspend(struct device *dev)
 {
@@ -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,
 	.driver		= {
 		.name	= "imx-drm",
 		.pm	= &imx_drm_pm_ops,