[PATCH 0/2] media: amlogic: handle C3 MIPI runtime resume failures

[PATCH 0/2] media: amlogic: handle C3 MIPI runtime resume failures

[Jiale Yao]

The C3 MIPI adapter and CSI-2 receiver ignore failures from
pm_runtime_resume_and_get() when enabling streams. Both drivers then access
registers while their power domains may be unavailable, report streaming as
enabled, and later drop runtime PM references that were not acquired.

Check and propagate the runtime PM errors before either device is
programmed.

Jiale Yao (2):
  media: c3-mipi-adap: handle runtime resume failure
  media: c3-mipi-csi2: handle runtime resume failure

 drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c | 4 +++-
 drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c    | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

-- 
2.34.1

[PATCH 1/2] media: c3-mipi-adap: handle runtime resume failure

[Jiale Yao]

c3_mipi_adap_enable_streams() ignores runtime resume failures and
continues programming adapter registers before reporting that streaming
started. If the power domain could not be resumed, those register
accesses are unsafe and the disable path later drops a reference that
was not acquired.

Return the runtime PM error before accessing the adapter.

Fixes: f0d2d8062cc8 ("media: platform: Add C3 MIPI adapter driver")
Signed-off-by: Jiale Yao <yaojiale02@163.com>
---
 drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c b/drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c
index 4bd98fb9c7e9..750b301f4bbf 100644
--- a/drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c
+++ b/drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c
@@ -455,7 +455,9 @@ static int c3_mipi_adap_enable_streams(struct v4l2_subdev *sd,
 
 	src_sd = media_entity_to_v4l2_subdev(adap->src_pad->entity);
 
-	pm_runtime_resume_and_get(adap->dev);
+	ret = pm_runtime_resume_and_get(adap->dev);
+	if (ret < 0)
+		return ret;
 
 	fmt = v4l2_subdev_state_get_format(state, C3_MIPI_ADAP_PAD_SINK);
 
-- 
2.34.1

Re: [PATCH 1/2] media: c3-mipi-adap: handle runtime resume failure

[Keke Li]

Hi Jiale,

Thanks for your patch.

On 10/3/26 16:11, Jiale Yao wrote:
> [You don't often get email from yaojiale02@163.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> [ EXTERNAL EMAIL ]
>
> c3_mipi_adap_enable_streams() ignores runtime resume failures and
> continues programming adapter registers before reporting that streaming
> started. If the power domain could not be resumed, those register
> accesses are unsafe and the disable path later drops a reference that
> was not acquired.
>
> Return the runtime PM error before accessing the adapter.
>
> Fixes: f0d2d8062cc8 ("media: platform: Add C3 MIPI adapter driver")
> Signed-off-by: Jiale Yao <yaojiale02@163.com>
> ---
>   drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c b/drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c
> index 4bd98fb9c7e9..750b301f4bbf 100644
> --- a/drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c
> +++ b/drivers/media/platform/amlogic/c3/mipi-adapter/c3-mipi-adap.c
> @@ -455,7 +455,9 @@ static int c3_mipi_adap_enable_streams(struct v4l2_subdev *sd,
>
>          src_sd = media_entity_to_v4l2_subdev(adap->src_pad->entity);
>
> -       pm_runtime_resume_and_get(adap->dev);
> +       ret = pm_runtime_resume_and_get(adap->dev);
> +       if (ret < 0)

                     Is   ' if (ret)'  better?

       Thanks!

> +               return ret;
>
>          fmt = v4l2_subdev_state_get_format(state, C3_MIPI_ADAP_PAD_SINK);
>
> --
> 2.34.1
>

[PATCH 2/2] media: c3-mipi-csi2: handle runtime resume failure

[Jiale Yao]

c3_mipi_csi_enable_streams() ignores runtime resume failures and starts
the receiver before reporting that streaming is enabled. If the power
domain could not be resumed, this accesses unavailable registers and
the disable path later drops a reference that was not acquired.

Return the runtime PM error before starting the receiver.

Fixes: b63ef604a28d ("media: platform: Add C3 MIPI CSI-2 driver")
Signed-off-by: Jiale Yao <yaojiale02@163.com>
---
 drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c b/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
index b9e4ef3fc308..4731d58bf2dd 100644
--- a/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
+++ b/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
@@ -431,7 +431,9 @@ static int c3_mipi_csi_enable_streams(struct v4l2_subdev *sd,
 
 	src_sd = media_entity_to_v4l2_subdev(csi->src_pad->entity);
 
-	pm_runtime_resume_and_get(csi->dev);
+	ret = pm_runtime_resume_and_get(csi->dev);
+	if (ret < 0)
+		return ret;
 
 	c3_mipi_csi_start_stream(csi);
 
-- 
2.34.1

Re: [PATCH 2/2] media: c3-mipi-csi2: handle runtime resume failure

[Keke Li]

Hi Jiale,

On 10/3/26 16:11, Jiale Yao wrote:
> [You don't often get email from yaojiale02@163.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> [ EXTERNAL EMAIL ]
>
> c3_mipi_csi_enable_streams() ignores runtime resume failures and starts
> the receiver before reporting that streaming is enabled. If the power
> domain could not be resumed, this accesses unavailable registers and
> the disable path later drops a reference that was not acquired.
>
> Return the runtime PM error before starting the receiver.
>
> Fixes: b63ef604a28d ("media: platform: Add C3 MIPI CSI-2 driver")
> Signed-off-by: Jiale Yao <yaojiale02@163.com>
> ---
>   drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c b/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
> index b9e4ef3fc308..4731d58bf2dd 100644
> --- a/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
> +++ b/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
> @@ -431,7 +431,9 @@ static int c3_mipi_csi_enable_streams(struct v4l2_subdev *sd,
>
>          src_sd = media_entity_to_v4l2_subdev(csi->src_pad->entity);
>
> -       pm_runtime_resume_and_get(csi->dev);
> +       ret = pm_runtime_resume_and_get(csi->dev);
> +       if (ret < 0)
Is   ' if (ret)'  better?
> +               return ret;
>
>          c3_mipi_csi_start_stream(csi);
>
> --
> 2.34.1
>

Re: [PATCH 2/2] media: c3-mipi-csi2: handle runtime resume failure

[Jacopo Mondi]

Hi Keke

On Mon, Oct 19, 2026 at 02:24:34PM +0800, Keke Li wrote:
> Hi Jiale,
>
> On 10/3/26 16:11, Jiale Yao wrote:
> > [You don't often get email from yaojiale02@163.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> >
> > [ EXTERNAL EMAIL ]
> >
> > c3_mipi_csi_enable_streams() ignores runtime resume failures and starts
> > the receiver before reporting that streaming is enabled. If the power
> > domain could not be resumed, this accesses unavailable registers and
> > the disable path later drops a reference that was not acquired.
> >
> > Return the runtime PM error before starting the receiver.
> >
> > Fixes: b63ef604a28d ("media: platform: Add C3 MIPI CSI-2 driver")
> > Signed-off-by: Jiale Yao <yaojiale02@163.com>
> > ---
> >   drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c b/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
> > index b9e4ef3fc308..4731d58bf2dd 100644
> > --- a/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
> > +++ b/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
> > @@ -431,7 +431,9 @@ static int c3_mipi_csi_enable_streams(struct v4l2_subdev *sd,
> >
> >          src_sd = media_entity_to_v4l2_subdev(csi->src_pad->entity);
> >
> > -       pm_runtime_resume_and_get(csi->dev);
> > +       ret = pm_runtime_resume_and_get(csi->dev);
> > +       if (ret < 0)
> Is   ' if (ret)'  better?

Does your driver depend on select PM ? It doesn't seem the case to me.

If PM is disabled pm_runtime_resume_and_get() returns 1
if my reading of

        static inline int __pm_runtime_resume(struct device *dev, int rpmflags)
        {
                return 1;
        }

is correct.

If you
        if (ret)

also this case will be caught as an error, while we instead want to
continue as the peripheral is meant to stay powered on from probe() if
CONFIG_PM is not selected.

(I quickly had a look at the csi2 driver probe() routine
c3_mipi_csi_probe() and it doesn't seem to power up the interface in
probe() to support !CONFIG_PM. Personally, I would just select PM
unconditionally almost everywhere these days and be done with it).

> > +               return ret;
> >
> >          c3_mipi_csi_start_stream(csi);
> >
> > --
> > 2.34.1
> >

Re: [PATCH 2/2] media: c3-mipi-csi2: handle runtime resume failure

[Keke Li]

Hi Jacopo,

Thanks for your reply.

On 10/19/26 15:31, Jacopo Mondi wrote:
> [ EXTERNAL EMAIL ]
>
> Hi Keke
>
> On Mon, Oct 19, 2026 at 02:24:34PM +0800, Keke Li wrote:
>> Hi Jiale,
>>
>> On 10/3/26 16:11, Jiale Yao wrote:
>>> [You don't often get email from yaojiale02@163.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>>
>>> [ EXTERNAL EMAIL ]
>>>
>>> c3_mipi_csi_enable_streams() ignores runtime resume failures and starts
>>> the receiver before reporting that streaming is enabled. If the power
>>> domain could not be resumed, this accesses unavailable registers and
>>> the disable path later drops a reference that was not acquired.
>>>
>>> Return the runtime PM error before starting the receiver.
>>>
>>> Fixes: b63ef604a28d ("media: platform: Add C3 MIPI CSI-2 driver")
>>> Signed-off-by: Jiale Yao <yaojiale02@163.com>
>>> ---
>>>    drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c | 4 +++-
>>>    1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c b/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
>>> index b9e4ef3fc308..4731d58bf2dd 100644
>>> --- a/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
>>> +++ b/drivers/media/platform/amlogic/c3/mipi-csi2/c3-mipi-csi2.c
>>> @@ -431,7 +431,9 @@ static int c3_mipi_csi_enable_streams(struct v4l2_subdev *sd,
>>>
>>>           src_sd = media_entity_to_v4l2_subdev(csi->src_pad->entity);
>>>
>>> -       pm_runtime_resume_and_get(csi->dev);
>>> +       ret = pm_runtime_resume_and_get(csi->dev);
>>> +       if (ret < 0)
>> Is   ' if (ret)'  better?
>> Does your driver depend on select PM ? It doesn't seem the case to me.
>>
>> If PM is disabled pm_runtime_resume_and_get() returns 1
>> if my reading of
>>
>>          static inline int __pm_runtime_resume(struct device *dev, int rpmflags)
>>          {
>>                  return 1;
>>          }
>>
>> is correct.
>>
>> If you
>>          if (ret)
>>
>> also this case will be caught as an error, while we instead want to
>> continue as the peripheral is meant to stay powered on from probe() if
>> CONFIG_PM is not selected.
>>
>> (I quickly had a look at the csi2 driver probe() routine
>> c3_mipi_csi_probe() and it doesn't seem to power up the interface in
>> probe() to support !CONFIG_PM. Personally, I would just select PM
>> unconditionally almost everywhere these days and be done with it).

Yes, you are correct.🙂

a. Here should keep 'if (ret < 0)'.

b. Add 'select PM' in each Kconfig file.

Thanks very much!

>>> +               return ret;
>>>
>>>           c3_mipi_csi_start_stream(csi);
>>>
>>> --
>>> 2.34.1
>>>