[1/2] drm/dp_aux: Use non-cyclic idr, add suffix option for aux device
diff mbox series

Message ID 1555085131-8716-2-git-send-email-sunpeng.li@amd.com
State New
Headers show
Series
  • Add AUX device entries for DP MST devices
Related show

Commit Message

Leo April 12, 2019, 4:05 p.m. UTC
From: Leo Li <sunpeng.li@amd.com>

In preparation for adding aux devices for DP MST:

1. A non-cyclic idr is used for the device minor version. That way,
   hotplug cycling MST devices won't needlessly increment the minor
   version index.
2. A suffix option is added to the aux device file name. It can be used
   to identify the corresponding MST device.

Signed-off-by: Leo Li <sunpeng.li@amd.com>
---
 drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
 drivers/gpu/drm/drm_dp_aux_dev.c           | 8 ++++----
 drivers/gpu/drm/drm_dp_helper.c            | 2 +-
 3 files changed, 8 insertions(+), 7 deletions(-)

Comments

Lyude Paul April 16, 2019, 10:16 p.m. UTC | #1
Sorry for the slow response, I've been really busy ;_;

On Fri, 2019-04-12 at 12:05 -0400, sunpeng.li@amd.com wrote:
> From: Leo Li <sunpeng.li@amd.com>
> 
> In preparation for adding aux devices for DP MST:
> 
> 1. A non-cyclic idr is used for the device minor version. That way,
>    hotplug cycling MST devices won't needlessly increment the minor
>    version index.

I really like this btw, cyclic idrs are really annoying for drm_dp_aux_dev,
even outside of MST (try reloading a drm driver a couple of times and you'll
understand ;). I think we should split this into another commit though

> 2. A suffix option is added to the aux device file name. It can be used
>    to identify the corresponding MST device.

I like this idea, but I think there may be a better way that we can do this.
Using /dev/nvme* as an example, we have the standard dev paths (/dev/nvme0,
/dev/nvme0n1, etc.). But we can also access them through /dev/disk/by-
{id,label,partlabel,partuuid,path,uuid}.

So what if we added something similar for aux devices? We start off with the
standard /dev/drm_dp_aux*, then provide more descriptive symlinks and
directories:

(feel free to come up with better naming then this if you can)

/dev/drm_dp_aux/card0-DP-1 -> /dev/drm_dp_aux1
/dev/drm_dp_aux/card0-DP-2 -> /dev/drm_dp_aux2
etc.

> 
> Signed-off-by: Leo Li <sunpeng.li@amd.com>
> ---
>  drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
>  drivers/gpu/drm/drm_dp_aux_dev.c           | 8 ++++----
>  drivers/gpu/drm/drm_dp_helper.c            | 2 +-
>  3 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h
> b/drivers/gpu/drm/drm_crtc_helper_internal.h
> index b5ac158..9f0907b 100644
> --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
> @@ -46,7 +46,7 @@ static inline int drm_fb_helper_modinit(void)
>  #ifdef CONFIG_DRM_DP_AUX_CHARDEV
>  int drm_dp_aux_dev_init(void);
>  void drm_dp_aux_dev_exit(void);
> -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
> +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char
> *suffix);
>  void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
>  #else
>  static inline int drm_dp_aux_dev_init(void)
> @@ -58,7 +58,8 @@ static inline void drm_dp_aux_dev_exit(void)
>  {
>  }
>  
> -static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
> +static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
> +					      const char *suffix)
>  {
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c
> b/drivers/gpu/drm/drm_dp_aux_dev.c
> index 0e4f25d..2310a67 100644
> --- a/drivers/gpu/drm/drm_dp_aux_dev.c
> +++ b/drivers/gpu/drm/drm_dp_aux_dev.c
> @@ -80,8 +80,7 @@ static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct
> drm_dp_aux *aux)
>  	kref_init(&aux_dev->refcount);
>  
>  	mutex_lock(&aux_idr_mutex);
> -	index = idr_alloc_cyclic(&aux_idr, aux_dev, 0, DRM_AUX_MINORS,
> -				 GFP_KERNEL);
> +	index = idr_alloc(&aux_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
>  	mutex_unlock(&aux_idr_mutex);
>  	if (index < 0) {
>  		kfree(aux_dev);
> @@ -290,7 +289,7 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux
> *aux)
>  	kref_put(&aux_dev->refcount, release_drm_dp_aux_dev);
>  }
>  
> -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
> +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix)
>  {
>  	struct drm_dp_aux_dev *aux_dev;
>  	int res;
> @@ -301,7 +300,8 @@ int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
>  
>  	aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
>  				     MKDEV(drm_dev_major, aux_dev->index),
> NULL,
> -				     "drm_dp_aux%d", aux_dev->index);
> +				     "drm_dp_aux%d%s", aux_dev->index,
> +				     suffix ? suffix : "");
>  	if (IS_ERR(aux_dev->dev)) {
>  		res = PTR_ERR(aux_dev->dev);
>  		aux_dev->dev = NULL;
> diff --git a/drivers/gpu/drm/drm_dp_helper.c
> b/drivers/gpu/drm/drm_dp_helper.c
> index e2266ac..13f1005 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -1143,7 +1143,7 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
>  	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
>  		sizeof(aux->ddc.name));
>  
> -	ret = drm_dp_aux_register_devnode(aux);
> +	ret = drm_dp_aux_register_devnode(aux, NULL);
>  	if (ret)
>  		return ret;
>
Leo April 17, 2019, 11:10 p.m. UTC | #2
On 2019-04-16 6:16 p.m., Lyude Paul wrote:
> Sorry for the slow response, I've been really busy ;_;

No worries :)

> 
> On Fri, 2019-04-12 at 12:05 -0400, sunpeng.li@amd.com wrote:
>> From: Leo Li <sunpeng.li@amd.com>
>>
>> In preparation for adding aux devices for DP MST:
>>
>> 1. A non-cyclic idr is used for the device minor version. That way,
>>     hotplug cycling MST devices won't needlessly increment the minor
>>     version index.
> 
> I really like this btw, cyclic idrs are really annoying for drm_dp_aux_dev,
> even outside of MST (try reloading a drm driver a couple of times and you'll
> understand ;). I think we should split this into another commit though
> 
>> 2. A suffix option is added to the aux device file name. It can be used
>>     to identify the corresponding MST device.
> 
> I like this idea, but I think there may be a better way that we can do this.
> Using /dev/nvme* as an example, we have the standard dev paths (/dev/nvme0,
> /dev/nvme0n1, etc.). But we can also access them through /dev/disk/by-
> {id,label,partlabel,partuuid,path,uuid}.
> 
> So what if we added something similar for aux devices? We start off with the
> standard /dev/drm_dp_aux*, then provide more descriptive symlinks and
> directories:
> 
> (feel free to come up with better naming then this if you can)
> 
> /dev/drm_dp_aux/card0-DP-1 -> /dev/drm_dp_aux1
> /dev/drm_dp_aux/card0-DP-2 -> /dev/drm_dp_aux2
> etc.

That does sound neater - although FWICT, this will have to be done with
udev rules?

I took a brief look at how that's done for storage devices. It looks
like they have rules defined in
/lib/udev/rules.d/60-persistent-storage.rules that manages the "by-x"
symlinks.

To make this happen for aux devices, what we could do is attach sysfs
attributes to the device. It can then be parsed by udev in a similar
fashion. Currently, only 'name' attribute is attached, as seen in
drm_dp_aux_dev.c (after name_show()).

Thanks,
Leo

> 
>>
>> Signed-off-by: Leo Li <sunpeng.li@amd.com>
>> ---
>>   drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
>>   drivers/gpu/drm/drm_dp_aux_dev.c           | 8 ++++----
>>   drivers/gpu/drm/drm_dp_helper.c            | 2 +-
>>   3 files changed, 8 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h
>> b/drivers/gpu/drm/drm_crtc_helper_internal.h
>> index b5ac158..9f0907b 100644
>> --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
>> +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
>> @@ -46,7 +46,7 @@ static inline int drm_fb_helper_modinit(void)
>>   #ifdef CONFIG_DRM_DP_AUX_CHARDEV
>>   int drm_dp_aux_dev_init(void);
>>   void drm_dp_aux_dev_exit(void);
>> -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
>> +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char
>> *suffix);
>>   void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
>>   #else
>>   static inline int drm_dp_aux_dev_init(void)
>> @@ -58,7 +58,8 @@ static inline void drm_dp_aux_dev_exit(void)
>>   {
>>   }
>>   
>> -static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
>> +static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
>> +					      const char *suffix)
>>   {
>>   	return 0;
>>   }
>> diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c
>> b/drivers/gpu/drm/drm_dp_aux_dev.c
>> index 0e4f25d..2310a67 100644
>> --- a/drivers/gpu/drm/drm_dp_aux_dev.c
>> +++ b/drivers/gpu/drm/drm_dp_aux_dev.c
>> @@ -80,8 +80,7 @@ static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct
>> drm_dp_aux *aux)
>>   	kref_init(&aux_dev->refcount);
>>   
>>   	mutex_lock(&aux_idr_mutex);
>> -	index = idr_alloc_cyclic(&aux_idr, aux_dev, 0, DRM_AUX_MINORS,
>> -				 GFP_KERNEL);
>> +	index = idr_alloc(&aux_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
>>   	mutex_unlock(&aux_idr_mutex);
>>   	if (index < 0) {
>>   		kfree(aux_dev);
>> @@ -290,7 +289,7 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux
>> *aux)
>>   	kref_put(&aux_dev->refcount, release_drm_dp_aux_dev);
>>   }
>>   
>> -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
>> +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix)
>>   {
>>   	struct drm_dp_aux_dev *aux_dev;
>>   	int res;
>> @@ -301,7 +300,8 @@ int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
>>   
>>   	aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
>>   				     MKDEV(drm_dev_major, aux_dev->index),
>> NULL,
>> -				     "drm_dp_aux%d", aux_dev->index);
>> +				     "drm_dp_aux%d%s", aux_dev->index,
>> +				     suffix ? suffix : "");
>>   	if (IS_ERR(aux_dev->dev)) {
>>   		res = PTR_ERR(aux_dev->dev);
>>   		aux_dev->dev = NULL;
>> diff --git a/drivers/gpu/drm/drm_dp_helper.c
>> b/drivers/gpu/drm/drm_dp_helper.c
>> index e2266ac..13f1005 100644
>> --- a/drivers/gpu/drm/drm_dp_helper.c
>> +++ b/drivers/gpu/drm/drm_dp_helper.c
>> @@ -1143,7 +1143,7 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
>>   	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
>>   		sizeof(aux->ddc.name));
>>   
>> -	ret = drm_dp_aux_register_devnode(aux);
>> +	ret = drm_dp_aux_register_devnode(aux, NULL);
>>   	if (ret)
>>   		return ret;
>>
Lyude Paul April 22, 2019, 5:39 p.m. UTC | #3
On Wed, 2019-04-17 at 23:10 +0000, Li, Sun peng (Leo) wrote:
> 
> 
> On 2019-04-16 6:16 p.m., Lyude Paul wrote:
> > Sorry for the slow response, I've been really busy ;_;
> 
> No worries :)
> 
> > On Fri, 2019-04-12 at 12:05 -0400, sunpeng.li@amd.com wrote:
> > > From: Leo Li <sunpeng.li@amd.com>
> > > 
> > > In preparation for adding aux devices for DP MST:
> > > 
> > > 1. A non-cyclic idr is used for the device minor version. That way,
> > >     hotplug cycling MST devices won't needlessly increment the minor
> > >     version index.
> > 
> > I really like this btw, cyclic idrs are really annoying for drm_dp_aux_dev,
> > even outside of MST (try reloading a drm driver a couple of times and you'll
> > understand ;). I think we should split this into another commit though
> > 
> > > 2. A suffix option is added to the aux device file name. It can be used
> > >     to identify the corresponding MST device.
> > 
> > I like this idea, but I think there may be a better way that we can do this.
> > Using /dev/nvme* as an example, we have the standard dev paths (/dev/nvme0,
> > /dev/nvme0n1, etc.). But we can also access them through /dev/disk/by-
> > {id,label,partlabel,partuuid,path,uuid}.
> > 
> > So what if we added something similar for aux devices? We start off with the
> > standard /dev/drm_dp_aux*, then provide more descriptive symlinks and
> > directories:
> > 
> > (feel free to come up with better naming then this if you can)
> > 
> > /dev/drm_dp_aux/card0-DP-1 -> /dev/drm_dp_aux1
> > /dev/drm_dp_aux/card0-DP-2 -> /dev/drm_dp_aux2
> > etc.
> 
> That does sound neater - although FWICT, this will have to be done with
> udev rules?
> 
> I took a brief look at how that's done for storage devices. It looks
> like they have rules defined in
> /lib/udev/rules.d/60-persistent-storage.rules that manages the "by-x"
> symlinks.
> 
> To make this happen for aux devices, what we could do is attach sysfs
> attributes to the device. It can then be parsed by udev in a similar
> fashion. Currently, only 'name' attribute is attached, as seen in
> drm_dp_aux_dev.c (after name_show()).

Yeah-that sounds perfect to me!

> 
> Thanks,
> Leo
> 
> > > Signed-off-by: Leo Li <sunpeng.li@amd.com>
> > > ---
> > >   drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
> > >   drivers/gpu/drm/drm_dp_aux_dev.c           | 8 ++++----
> > >   drivers/gpu/drm/drm_dp_helper.c            | 2 +-
> > >   3 files changed, 8 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h
> > > b/drivers/gpu/drm/drm_crtc_helper_internal.h
> > > index b5ac158..9f0907b 100644
> > > --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
> > > +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
> > > @@ -46,7 +46,7 @@ static inline int drm_fb_helper_modinit(void)
> > >   #ifdef CONFIG_DRM_DP_AUX_CHARDEV
> > >   int drm_dp_aux_dev_init(void);
> > >   void drm_dp_aux_dev_exit(void);
> > > -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
> > > +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char
> > > *suffix);
> > >   void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
> > >   #else
> > >   static inline int drm_dp_aux_dev_init(void)
> > > @@ -58,7 +58,8 @@ static inline void drm_dp_aux_dev_exit(void)
> > >   {
> > >   }
> > >   
> > > -static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
> > > +static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
> > > +					      const char *suffix)
> > >   {
> > >   	return 0;
> > >   }
> > > diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c
> > > b/drivers/gpu/drm/drm_dp_aux_dev.c
> > > index 0e4f25d..2310a67 100644
> > > --- a/drivers/gpu/drm/drm_dp_aux_dev.c
> > > +++ b/drivers/gpu/drm/drm_dp_aux_dev.c
> > > @@ -80,8 +80,7 @@ static struct drm_dp_aux_dev
> > > *alloc_drm_dp_aux_dev(struct
> > > drm_dp_aux *aux)
> > >   	kref_init(&aux_dev->refcount);
> > >   
> > >   	mutex_lock(&aux_idr_mutex);
> > > -	index = idr_alloc_cyclic(&aux_idr, aux_dev, 0, DRM_AUX_MINORS,
> > > -				 GFP_KERNEL);
> > > +	index = idr_alloc(&aux_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
> > >   	mutex_unlock(&aux_idr_mutex);
> > >   	if (index < 0) {
> > >   		kfree(aux_dev);
> > > @@ -290,7 +289,7 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux
> > > *aux)
> > >   	kref_put(&aux_dev->refcount, release_drm_dp_aux_dev);
> > >   }
> > >   
> > > -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
> > > +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char
> > > *suffix)
> > >   {
> > >   	struct drm_dp_aux_dev *aux_dev;
> > >   	int res;
> > > @@ -301,7 +300,8 @@ int drm_dp_aux_register_devnode(struct drm_dp_aux
> > > *aux)
> > >   
> > >   	aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
> > >   				     MKDEV(drm_dev_major, aux_dev-
> > > >index),
> > > NULL,
> > > -				     "drm_dp_aux%d", aux_dev->index);
> > > +				     "drm_dp_aux%d%s", aux_dev->index,
> > > +				     suffix ? suffix : "");
> > >   	if (IS_ERR(aux_dev->dev)) {
> > >   		res = PTR_ERR(aux_dev->dev);
> > >   		aux_dev->dev = NULL;
> > > diff --git a/drivers/gpu/drm/drm_dp_helper.c
> > > b/drivers/gpu/drm/drm_dp_helper.c
> > > index e2266ac..13f1005 100644
> > > --- a/drivers/gpu/drm/drm_dp_helper.c
> > > +++ b/drivers/gpu/drm/drm_dp_helper.c
> > > @@ -1143,7 +1143,7 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
> > >   	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux-
> > > >dev),
> > >   		sizeof(aux->ddc.name));
> > >   
> > > -	ret = drm_dp_aux_register_devnode(aux);
> > > +	ret = drm_dp_aux_register_devnode(aux, NULL);
> > >   	if (ret)
> > >   		return ret;
> > >

Patch
diff mbox series

diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h b/drivers/gpu/drm/drm_crtc_helper_internal.h
index b5ac158..9f0907b 100644
--- a/drivers/gpu/drm/drm_crtc_helper_internal.h
+++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
@@ -46,7 +46,7 @@  static inline int drm_fb_helper_modinit(void)
 #ifdef CONFIG_DRM_DP_AUX_CHARDEV
 int drm_dp_aux_dev_init(void);
 void drm_dp_aux_dev_exit(void);
-int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
+int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix);
 void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
 #else
 static inline int drm_dp_aux_dev_init(void)
@@ -58,7 +58,8 @@  static inline void drm_dp_aux_dev_exit(void)
 {
 }
 
-static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
+static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
+					      const char *suffix)
 {
 	return 0;
 }
diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c b/drivers/gpu/drm/drm_dp_aux_dev.c
index 0e4f25d..2310a67 100644
--- a/drivers/gpu/drm/drm_dp_aux_dev.c
+++ b/drivers/gpu/drm/drm_dp_aux_dev.c
@@ -80,8 +80,7 @@  static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct drm_dp_aux *aux)
 	kref_init(&aux_dev->refcount);
 
 	mutex_lock(&aux_idr_mutex);
-	index = idr_alloc_cyclic(&aux_idr, aux_dev, 0, DRM_AUX_MINORS,
-				 GFP_KERNEL);
+	index = idr_alloc(&aux_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
 	mutex_unlock(&aux_idr_mutex);
 	if (index < 0) {
 		kfree(aux_dev);
@@ -290,7 +289,7 @@  void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux)
 	kref_put(&aux_dev->refcount, release_drm_dp_aux_dev);
 }
 
-int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
+int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix)
 {
 	struct drm_dp_aux_dev *aux_dev;
 	int res;
@@ -301,7 +300,8 @@  int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
 
 	aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
 				     MKDEV(drm_dev_major, aux_dev->index), NULL,
-				     "drm_dp_aux%d", aux_dev->index);
+				     "drm_dp_aux%d%s", aux_dev->index,
+				     suffix ? suffix : "");
 	if (IS_ERR(aux_dev->dev)) {
 		res = PTR_ERR(aux_dev->dev);
 		aux_dev->dev = NULL;
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index e2266ac..13f1005 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1143,7 +1143,7 @@  int drm_dp_aux_register(struct drm_dp_aux *aux)
 	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
 		sizeof(aux->ddc.name));
 
-	ret = drm_dp_aux_register_devnode(aux);
+	ret = drm_dp_aux_register_devnode(aux, NULL);
 	if (ret)
 		return ret;