media: mali-c55: Fix NULL dev stream alert for tpg sub-device

[PATCH] media: mali-c55: Fix NULL dev stream alert for tpg sub-device

Posted by jempty.liang 3 weeks, 4 days ago

Fix "(NULL device *): collect_streams: sub-device 'mali-c55 tpg'
does not support streams" by setting `sd->dev = mali_c55->dev`
for isp/resizer/tpg modules.

Signed-off-by: jempty.liang <imntjempty@163.com>
---
 drivers/media/platform/arm/mali-c55/mali-c55-isp.c     | 1 +
 drivers/media/platform/arm/mali-c55/mali-c55-resizer.c | 1 +
 drivers/media/platform/arm/mali-c55/mali-c55-tpg.c     | 1 +
 3 files changed, 3 insertions(+)

diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-isp.c b/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
index 497f25fbdd13..ce84aad9f1d5 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
@@ -610,6 +610,7 @@ int mali_c55_register_isp(struct mali_c55 *mali_c55)
 	sd->entity.ops = &mali_c55_isp_media_ops;
 	sd->entity.function = MEDIA_ENT_F_PROC_VIDEO_ISP;
 	sd->internal_ops = &mali_c55_isp_internal_ops;
+	sd->dev = mali_c55->dev;
 	strscpy(sd->name, MALI_C55_DRIVER_NAME " isp", sizeof(sd->name));
 
 	isp->pads[MALI_C55_ISP_PAD_SINK_VIDEO].flags = MEDIA_PAD_FL_SINK |
diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-resizer.c b/drivers/media/platform/arm/mali-c55/mali-c55-resizer.c
index a8d739af74b6..c4f46651dcee 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-resizer.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-resizer.c
@@ -1070,6 +1070,7 @@ static int mali_c55_register_resizer(struct mali_c55 *mali_c55,
 	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_STREAMS;
 	sd->entity.function = MEDIA_ENT_F_PROC_VIDEO_SCALER;
 	sd->internal_ops = &mali_c55_resizer_internal_ops;
+	sd->dev = mali_c55->dev;
 
 	rsz->pads[MALI_C55_RSZ_SINK_PAD].flags = MEDIA_PAD_FL_SINK;
 	rsz->pads[MALI_C55_RSZ_SOURCE_PAD].flags = MEDIA_PAD_FL_SOURCE;
diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-tpg.c b/drivers/media/platform/arm/mali-c55/mali-c55-tpg.c
index 1af5d2759a83..894f4cf377af 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-tpg.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-tpg.c
@@ -370,6 +370,7 @@ int mali_c55_register_tpg(struct mali_c55 *mali_c55)
 	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
 	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
 	sd->internal_ops = &mali_c55_tpg_internal_ops;
+	sd->dev = mali_c55->dev;
 	strscpy(sd->name, MALI_C55_DRIVER_NAME " tpg", sizeof(sd->name));
 
 	pad->flags = MEDIA_PAD_FL_SOURCE;
-- 
2.25.1

Re: [PATCH] media: mali-c55: Fix NULL dev stream alert for tpg sub-device

Posted by Jacopo Mondi 3 weeks, 4 days ago

Hi Jempty

On Tue, Jan 13, 2026 at 07:57:22AM +0000, jempty.liang wrote:
> Fix "(NULL device *): collect_streams: sub-device 'mali-c55 tpg'
> does not support streams" by setting `sd->dev = mali_c55->dev`
> for isp/resizer/tpg modules.

The missing device name in the error message is just a symptom, I
think this is a geniunely missing part of the subdevice initalization.

I would re-phrase this as

-------------------------------------------------------------------------------
The subdevices registered by the Mali-C55 driver do not have their
'struct device *dev' member initialized. This is visibile when looking
at debug message, as in example:

"(NULL device *): collect_streams: sub-device 'mali-c55 tpg' does not support streams"

Fix this by initializing the *dev field for each subdevice registered
by the Mali-C55 driver.
-------------------------------------------------------------------------------

I wonder if v4l2_device_register_subdev() shouldn't WARN or if return
an error if sd->dev is not initialized. Laurent, Sakari: opinions ?

Thanks
  j

>
> Signed-off-by: jempty.liang <imntjempty@163.com>
> ---
>  drivers/media/platform/arm/mali-c55/mali-c55-isp.c     | 1 +
>  drivers/media/platform/arm/mali-c55/mali-c55-resizer.c | 1 +
>  drivers/media/platform/arm/mali-c55/mali-c55-tpg.c     | 1 +
>  3 files changed, 3 insertions(+)
>
> diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-isp.c b/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
> index 497f25fbdd13..ce84aad9f1d5 100644
> --- a/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
> +++ b/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
> @@ -610,6 +610,7 @@ int mali_c55_register_isp(struct mali_c55 *mali_c55)
>  	sd->entity.ops = &mali_c55_isp_media_ops;
>  	sd->entity.function = MEDIA_ENT_F_PROC_VIDEO_ISP;
>  	sd->internal_ops = &mali_c55_isp_internal_ops;
> +	sd->dev = mali_c55->dev;
>  	strscpy(sd->name, MALI_C55_DRIVER_NAME " isp", sizeof(sd->name));
>
>  	isp->pads[MALI_C55_ISP_PAD_SINK_VIDEO].flags = MEDIA_PAD_FL_SINK |
> diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-resizer.c b/drivers/media/platform/arm/mali-c55/mali-c55-resizer.c
> index a8d739af74b6..c4f46651dcee 100644
> --- a/drivers/media/platform/arm/mali-c55/mali-c55-resizer.c
> +++ b/drivers/media/platform/arm/mali-c55/mali-c55-resizer.c
> @@ -1070,6 +1070,7 @@ static int mali_c55_register_resizer(struct mali_c55 *mali_c55,
>  	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_STREAMS;
>  	sd->entity.function = MEDIA_ENT_F_PROC_VIDEO_SCALER;
>  	sd->internal_ops = &mali_c55_resizer_internal_ops;
> +	sd->dev = mali_c55->dev;
>
>  	rsz->pads[MALI_C55_RSZ_SINK_PAD].flags = MEDIA_PAD_FL_SINK;
>  	rsz->pads[MALI_C55_RSZ_SOURCE_PAD].flags = MEDIA_PAD_FL_SOURCE;
> diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-tpg.c b/drivers/media/platform/arm/mali-c55/mali-c55-tpg.c
> index 1af5d2759a83..894f4cf377af 100644
> --- a/drivers/media/platform/arm/mali-c55/mali-c55-tpg.c
> +++ b/drivers/media/platform/arm/mali-c55/mali-c55-tpg.c
> @@ -370,6 +370,7 @@ int mali_c55_register_tpg(struct mali_c55 *mali_c55)
>  	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
>  	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
>  	sd->internal_ops = &mali_c55_tpg_internal_ops;
> +	sd->dev = mali_c55->dev;
>  	strscpy(sd->name, MALI_C55_DRIVER_NAME " tpg", sizeof(sd->name));
>
>  	pad->flags = MEDIA_PAD_FL_SOURCE;
> --
> 2.25.1
>

Re: [PATCH] media: mali-c55: Fix NULL dev stream alert for tpg sub-device

Posted by Sakari Ailus 3 weeks, 4 days ago

Hi Jacopo,

On Tue, Jan 13, 2026 at 09:55:10AM +0100, Jacopo Mondi wrote:
> I wonder if v4l2_device_register_subdev() shouldn't WARN or if return
> an error if sd->dev is not initialized. Laurent, Sakari: opinions ?

I might even return an error but I wonder what would break. Perhaps indeed
could start with a warning?

-- 
Sakari Ailus

Re: [PATCH] media: mali-c55: Fix NULL dev stream alert for tpg sub-device

Posted by Dan Scally 3 weeks, 4 days ago


On 13/01/2026 10:40, Sakari Ailus wrote:
> Hi Jacopo,
> 
> On Tue, Jan 13, 2026 at 09:55:10AM +0100, Jacopo Mondi wrote:
>> I wonder if v4l2_device_register_subdev() shouldn't WARN or if return
>> an error if sd->dev is not initialized. Laurent, Sakari: opinions ?
> 
> I might even return an error but I wonder what would break. Perhaps indeed
> could start with a warning?
> 

It looks like it's only used for dev_*() printks, unless I'm missing something. Thanks Jempty for 
spotting the problem!

Dan

Re: [PATCH] media: mali-c55: Fix NULL dev stream alert for tpg sub-device

Posted by Jacopo Mondi 3 weeks, 4 days ago

Hi Sakari

On Tue, Jan 13, 2026 at 12:40:25PM +0200, Sakari Ailus wrote:
> Hi Jacopo,
>
> On Tue, Jan 13, 2026 at 09:55:10AM +0100, Jacopo Mondi wrote:
> > I wonder if v4l2_device_register_subdev() shouldn't WARN or if return
> > an error if sd->dev is not initialized. Laurent, Sakari: opinions ?
>
> I might even return an error but I wonder what would break. Perhaps indeed
> could start with a warning?

I would start with:

--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -117,6 +117,13 @@ int __v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
        if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
                return -EINVAL;

+       /*
+        * Initializing sd->dev is mandatory. Warn for now to give faulty
+        * drivers a bit of time to update before actually returning an error.
+        */
+       WARN_ON(!sd->dev);
+
        /*
         * The reason to acquire the module here is to avoid unloading
         * a module of sub-device which is registered to a media

Would you like a patch ?

>
> --
> Sakari Ailus

Re: [PATCH] media: mali-c55: Fix NULL dev stream alert for tpg sub-device

Posted by Sakari Ailus 3 weeks, 3 days ago

Hi Jacopo,

On Tue, Jan 13, 2026 at 01:43:12PM +0100, Jacopo Mondi wrote:
> Hi Sakari
> 
> On Tue, Jan 13, 2026 at 12:40:25PM +0200, Sakari Ailus wrote:
> > Hi Jacopo,
> >
> > On Tue, Jan 13, 2026 at 09:55:10AM +0100, Jacopo Mondi wrote:
> > > I wonder if v4l2_device_register_subdev() shouldn't WARN or if return
> > > an error if sd->dev is not initialized. Laurent, Sakari: opinions ?
> >
> > I might even return an error but I wonder what would break. Perhaps indeed
> > could start with a warning?
> 
> I would start with:
> 
> --- a/drivers/media/v4l2-core/v4l2-device.c
> +++ b/drivers/media/v4l2-core/v4l2-device.c
> @@ -117,6 +117,13 @@ int __v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
>         if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
>                 return -EINVAL;
> 
> +       /*
> +        * Initializing sd->dev is mandatory. Warn for now to give faulty
> +        * drivers a bit of time to update before actually returning an error.
> +        */
> +       WARN_ON(!sd->dev);
> +
>         /*
>          * The reason to acquire the module here is to avoid unloading
>          * a module of sub-device which is registered to a media
> 
> Would you like a patch ?

Please. :-)

-- 
Kind regards,

Sakari Ailus