diff mbox series

[1/1] media: uvcvideo: Support devices that report an OT as an entity source

Message ID 20210308103128.33173-2-hdegoede@redhat.com
State Superseded
Headers show
Series [1/1] media: uvcvideo: Support devices that report an OT as an entity source | expand

Commit Message

Hans de Goede March 8, 2021, 10:31 a.m. UTC 
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Some devices reference an output terminal as the source of extension
units. This is incorrect, as output terminals only have an input pin,
and thus can't be connected to any entity in the forward direction. The
resulting topology would cause issues when registering the media
controller graph. To avoid this problem, connect the extension unit to
the source of the output terminal instead.

While at it, and while no device has been reported to be affected by
this issue, also handle forward scans where two output terminals would
be connected together, and skip the terminals found through such an
invalid connection.

Reported-and-tested-by: John Nealy <jnealy3@yahoo.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/media/usb/uvc/uvc_driver.c | 32 ++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

Comments

Hans de Goede March 31, 2021, 10:38 a.m. UTC | #1 
Hi All,

On 3/8/21 11:31 AM, Hans de Goede wrote:
> From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> 

> Some devices reference an output terminal as the source of extension

> units. This is incorrect, as output terminals only have an input pin,

> and thus can't be connected to any entity in the forward direction. The

> resulting topology would cause issues when registering the media

> controller graph. To avoid this problem, connect the extension unit to

> the source of the output terminal instead.

> 

> While at it, and while no device has been reported to be affected by

> this issue, also handle forward scans where two output terminals would

> be connected together, and skip the terminals found through such an

> invalid connection.

> 

> Reported-and-tested-by: John Nealy <jnealy3@yahoo.com>

> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> Signed-off-by: Hans de Goede <hdegoede@redhat.com>


Ping? This is a bug-fix which fixes a WARN triggering, causing many
users to see a backtrace in their kernel-logs and reporting bugs about this:

https://bugzilla.redhat.com/buglist.cgi?quicksearch=mc-entity.c

Currently shows 12 open bugs for this and this is not counting all the
ones which have already been triaged and matched as dups.

As such it would be really good if we can get this merged and on
its way to 5.12-rc# as a fix for 5.12 (and to be backported to the
stable series).

Regards,

Hans




> ---

>  drivers/media/usb/uvc/uvc_driver.c | 32 ++++++++++++++++++++++++++++++

>  1 file changed, 32 insertions(+)

> 

> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c

> index 30ef2a3110f7..8df58f04dac6 100644

> --- a/drivers/media/usb/uvc/uvc_driver.c

> +++ b/drivers/media/usb/uvc/uvc_driver.c

> @@ -1716,6 +1716,31 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain,

>  				return -EINVAL;

>  			}

>  

> +			/*

> +			 * Some devices reference an output terminal as the

> +			 * source of extension units. This is incorrect, as

> +			 * output terminals only have an input pin, and thus

> +			 * can't be connected to any entity in the forward

> +			 * direction. The resulting topology would cause issues

> +			 * when registering the media controller graph. To

> +			 * avoid this problem, connect the extension unit to

> +			 * the source of the output terminal instead.

> +			 */

> +			if (UVC_ENTITY_IS_OTERM(entity)) {

> +				struct uvc_entity *source;

> +

> +				source = uvc_entity_by_id(chain->dev,

> +							  entity->baSourceID[0]);

> +				if (!source) {

> +					uvc_dbg(chain->dev, DESCR,

> +						"Can't connect extension unit %u in chain\n",

> +						forward->id);

> +					break;

> +				}

> +

> +				forward->baSourceID[0] = source->id;

> +			}

> +

>  			list_add_tail(&forward->chain, &chain->entities);

>  			if (!found)

>  				uvc_dbg_cont(PROBE, " (->");

> @@ -1735,6 +1760,13 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain,

>  				return -EINVAL;

>  			}

>  

> +			if (UVC_ENTITY_IS_OTERM(entity)) {

> +				uvc_dbg(chain->dev, DESCR,

> +					"Unsupported connection between output terminals %u and %u\n",

> +					entity->id, forward->id);

> +				break;

> +			}

> +

>  			list_add_tail(&forward->chain, &chain->entities);

>  			if (!found)

>  				uvc_dbg_cont(PROBE, " (->");

>
Laurent Pinchart March 31, 2021, 11:03 a.m. UTC | #2 
Hi Hans,

On Wed, Mar 31, 2021 at 12:38:07PM +0200, Hans de Goede wrote:
> On 3/8/21 11:31 AM, Hans de Goede wrote:

> > From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> > 

> > Some devices reference an output terminal as the source of extension

> > units. This is incorrect, as output terminals only have an input pin,

> > and thus can't be connected to any entity in the forward direction. The

> > resulting topology would cause issues when registering the media

> > controller graph. To avoid this problem, connect the extension unit to

> > the source of the output terminal instead.

> > 

> > While at it, and while no device has been reported to be affected by

> > this issue, also handle forward scans where two output terminals would

> > be connected together, and skip the terminals found through such an

> > invalid connection.

> > 

> > Reported-and-tested-by: John Nealy <jnealy3@yahoo.com>

> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> > Signed-off-by: Hans de Goede <hdegoede@redhat.com>

> 

> Ping? This is a bug-fix which fixes a WARN triggering, causing many

> users to see a backtrace in their kernel-logs and reporting bugs about this:

> 

> https://bugzilla.redhat.com/buglist.cgi?quicksearch=mc-entity.c

> 

> Currently shows 12 open bugs for this and this is not counting all the

> ones which have already been triaged and matched as dups.

> 

> As such it would be really good if we can get this merged and on

> its way to 5.12-rc# as a fix for 5.12 (and to be backported to the

> stable series).


The patch is included in "[GIT PULL FOR v5.13] Miscellaneous changes". I
have no personal issue with it being merged in v5.12-rc, but technically
it's not a regression fix, is it ? I'll let Mauro decide what works best
for him.

> > ---

> >  drivers/media/usb/uvc/uvc_driver.c | 32 ++++++++++++++++++++++++++++++

> >  1 file changed, 32 insertions(+)

> > 

> > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c

> > index 30ef2a3110f7..8df58f04dac6 100644

> > --- a/drivers/media/usb/uvc/uvc_driver.c

> > +++ b/drivers/media/usb/uvc/uvc_driver.c

> > @@ -1716,6 +1716,31 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain,

> >  				return -EINVAL;

> >  			}

> >  

> > +			/*

> > +			 * Some devices reference an output terminal as the

> > +			 * source of extension units. This is incorrect, as

> > +			 * output terminals only have an input pin, and thus

> > +			 * can't be connected to any entity in the forward

> > +			 * direction. The resulting topology would cause issues

> > +			 * when registering the media controller graph. To

> > +			 * avoid this problem, connect the extension unit to

> > +			 * the source of the output terminal instead.

> > +			 */

> > +			if (UVC_ENTITY_IS_OTERM(entity)) {

> > +				struct uvc_entity *source;

> > +

> > +				source = uvc_entity_by_id(chain->dev,

> > +							  entity->baSourceID[0]);

> > +				if (!source) {

> > +					uvc_dbg(chain->dev, DESCR,

> > +						"Can't connect extension unit %u in chain\n",

> > +						forward->id);

> > +					break;

> > +				}

> > +

> > +				forward->baSourceID[0] = source->id;

> > +			}

> > +

> >  			list_add_tail(&forward->chain, &chain->entities);

> >  			if (!found)

> >  				uvc_dbg_cont(PROBE, " (->");

> > @@ -1735,6 +1760,13 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain,

> >  				return -EINVAL;

> >  			}

> >  

> > +			if (UVC_ENTITY_IS_OTERM(entity)) {

> > +				uvc_dbg(chain->dev, DESCR,

> > +					"Unsupported connection between output terminals %u and %u\n",

> > +					entity->id, forward->id);

> > +				break;

> > +			}

> > +

> >  			list_add_tail(&forward->chain, &chain->entities);

> >  			if (!found)

> >  				uvc_dbg_cont(PROBE, " (->");


-- 
Regards,

Laurent Pinchart
Hans de Goede March 31, 2021, 11:37 a.m. UTC | #3 
Hi,

On 3/31/21 1:03 PM, Laurent Pinchart wrote:
> Hi Hans,

> 

> On Wed, Mar 31, 2021 at 12:38:07PM +0200, Hans de Goede wrote:

>> On 3/8/21 11:31 AM, Hans de Goede wrote:

>>> From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>>>

>>> Some devices reference an output terminal as the source of extension

>>> units. This is incorrect, as output terminals only have an input pin,

>>> and thus can't be connected to any entity in the forward direction. The

>>> resulting topology would cause issues when registering the media

>>> controller graph. To avoid this problem, connect the extension unit to

>>> the source of the output terminal instead.

>>>

>>> While at it, and while no device has been reported to be affected by

>>> this issue, also handle forward scans where two output terminals would

>>> be connected together, and skip the terminals found through such an

>>> invalid connection.

>>>

>>> Reported-and-tested-by: John Nealy <jnealy3@yahoo.com>

>>> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

>>

>> Ping? This is a bug-fix which fixes a WARN triggering, causing many

>> users to see a backtrace in their kernel-logs and reporting bugs about this:

>>

>> https://bugzilla.redhat.com/buglist.cgi?quicksearch=mc-entity.c

>>

>> Currently shows 12 open bugs for this and this is not counting all the

>> ones which have already been triaged and matched as dups.

>>

>> As such it would be really good if we can get this merged and on

>> its way to 5.12-rc# as a fix for 5.12 (and to be backported to the

>> stable series).

> 

> The patch is included in "[GIT PULL FOR v5.13] Miscellaneous changes".


Ah I missed that.

> I have no personal issue with it being merged in v5.12-rc, but technically

> it's not a regression fix, is it ? I'll let Mauro decide what works best

> for him.


It is true that this is not a regression-fix but it is a bug-fix and for
a bug which users are actively hitting.

Regards,

Hans


> 

>>> ---

>>>  drivers/media/usb/uvc/uvc_driver.c | 32 ++++++++++++++++++++++++++++++

>>>  1 file changed, 32 insertions(+)

>>>

>>> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c

>>> index 30ef2a3110f7..8df58f04dac6 100644

>>> --- a/drivers/media/usb/uvc/uvc_driver.c

>>> +++ b/drivers/media/usb/uvc/uvc_driver.c

>>> @@ -1716,6 +1716,31 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain,

>>>  				return -EINVAL;

>>>  			}

>>>  

>>> +			/*

>>> +			 * Some devices reference an output terminal as the

>>> +			 * source of extension units. This is incorrect, as

>>> +			 * output terminals only have an input pin, and thus

>>> +			 * can't be connected to any entity in the forward

>>> +			 * direction. The resulting topology would cause issues

>>> +			 * when registering the media controller graph. To

>>> +			 * avoid this problem, connect the extension unit to

>>> +			 * the source of the output terminal instead.

>>> +			 */

>>> +			if (UVC_ENTITY_IS_OTERM(entity)) {

>>> +				struct uvc_entity *source;

>>> +

>>> +				source = uvc_entity_by_id(chain->dev,

>>> +							  entity->baSourceID[0]);

>>> +				if (!source) {

>>> +					uvc_dbg(chain->dev, DESCR,

>>> +						"Can't connect extension unit %u in chain\n",

>>> +						forward->id);

>>> +					break;

>>> +				}

>>> +

>>> +				forward->baSourceID[0] = source->id;

>>> +			}

>>> +

>>>  			list_add_tail(&forward->chain, &chain->entities);

>>>  			if (!found)

>>>  				uvc_dbg_cont(PROBE, " (->");

>>> @@ -1735,6 +1760,13 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain,

>>>  				return -EINVAL;

>>>  			}

>>>  

>>> +			if (UVC_ENTITY_IS_OTERM(entity)) {

>>> +				uvc_dbg(chain->dev, DESCR,

>>> +					"Unsupported connection between output terminals %u and %u\n",

>>> +					entity->id, forward->id);

>>> +				break;

>>> +			}

>>> +

>>>  			list_add_tail(&forward->chain, &chain->entities);

>>>  			if (!found)

>>>  				uvc_dbg_cont(PROBE, " (->");

>
diff mbox series

Patch

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 30ef2a3110f7..8df58f04dac6 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -1716,6 +1716,31 @@  static int uvc_scan_chain_forward(struct uvc_video_chain *chain,
 				return -EINVAL;
 			}
 
+			/*
+			 * Some devices reference an output terminal as the
+			 * source of extension units. This is incorrect, as
+			 * output terminals only have an input pin, and thus
+			 * can't be connected to any entity in the forward
+			 * direction. The resulting topology would cause issues
+			 * when registering the media controller graph. To
+			 * avoid this problem, connect the extension unit to
+			 * the source of the output terminal instead.
+			 */
+			if (UVC_ENTITY_IS_OTERM(entity)) {
+				struct uvc_entity *source;
+
+				source = uvc_entity_by_id(chain->dev,
+							  entity->baSourceID[0]);
+				if (!source) {
+					uvc_dbg(chain->dev, DESCR,
+						"Can't connect extension unit %u in chain\n",
+						forward->id);
+					break;
+				}
+
+				forward->baSourceID[0] = source->id;
+			}
+
 			list_add_tail(&forward->chain, &chain->entities);
 			if (!found)
 				uvc_dbg_cont(PROBE, " (->");
@@ -1735,6 +1760,13 @@  static int uvc_scan_chain_forward(struct uvc_video_chain *chain,
 				return -EINVAL;
 			}
 
+			if (UVC_ENTITY_IS_OTERM(entity)) {
+				uvc_dbg(chain->dev, DESCR,
+					"Unsupported connection between output terminals %u and %u\n",
+					entity->id, forward->id);
+				break;
+			}
+
 			list_add_tail(&forward->chain, &chain->entities);
 			if (!found)
 				uvc_dbg_cont(PROBE, " (->");