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From: Jacopo Mondi <jacopo@jmondi.org>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: "Sakari Ailus" <sakari.ailus@linux.intel.com>,
	"Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>,
	"Benoit Parrot" <bparrot@ti.com>,
	linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH v2 09/30] media: entity: Swap pads if route is checked from source to sink
Date: Mon, 18 Feb 2019 10:21:07 +0100
Message-ID: <20190218092107.omddljghnv3l2ss6@uno.localdomain> (raw)
In-Reply-To: <20190122152030.GB11461@pendragon.ideasonboard.com>

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Hi Laurent, Sakari,

On Tue, Jan 22, 2019 at 05:20:30PM +0200, Laurent Pinchart wrote:
> Hi Sakari,
>
> On Tue, Jan 22, 2019 at 05:15:06PM +0200, Sakari Ailus wrote:
> > On Wed, Jan 16, 2019 at 12:57:43AM +0200, Laurent Pinchart wrote:
> > >>
> > >> This way the pads are always passed to the has_route() op sink pad first.
> > >> Makes sense.
> > >
> > > Is there anything in the API that mandates one pad to be a sink and the
> > > other pad to the a source ? I had designed the operation to allow
> > > sink-sink and source-source connections to be checked too.
> >
> > Do you have a use case in mind for sink--sink or source--source routes? The
> > routes are about flows of data, so I'd presume only source--sink or
> > sink--source routes are meaningful.
> >
> > If you did, then the driver would have to handle that by itself. This still
> > simplifies the implementation for drivers that do not.
>
> I don't have use cases for such routes, but we use the has_route
> operation when traversing pipelines, and at that point we need to get
> all the internally connected pads. In another patch in this series you
> implement a helper function that handles this, but its implementation
> isn't complete. I explained in my review of that patch that I fear a
> correct generic implementation would become quite complex, while the
> complexity should be easy to handle on the driver side as the code can
> then be specialized for the case at hand.
>

As a compromise, in v3 I'm thinking of maintaining support for the
most common case of two sources connected to the same sink, as
Sakari's patch does, but let more complex cases be handled by the
driver implementation of has_route().

Ack?

> > > If your goal is to simplify the implementation of the .has_route()
> > > operation in drivers, I would instead sort pad0 and pad1 by value.
> >
> > That'd be another option to make the order deterministic for the driver.
> > I'm fine with that as well.
> >

In v3 I have taken both suggestions in: try the "sink then source" order
first, then order by index in case the pads are of the same time. This
needs to be documented in has_route() operation definition though.

Would that be fine with you?

Thanks
   j

> > >> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > >> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > >> ---
> > >>  drivers/media/media-entity.c | 4 ++++
> > >>  1 file changed, 4 insertions(+)
> > >>
> > >> diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
> > >> index 3c0e7425c8983b45..33f00e35ccd92c6f 100644
> > >> --- a/drivers/media/media-entity.c
> > >> +++ b/drivers/media/media-entity.c
> > >> @@ -249,6 +249,10 @@ bool media_entity_has_route(struct media_entity *entity, unsigned int pad0,
> > >>  	if (!entity->ops || !entity->ops->has_route)
> > >>  		return true;
> > >>
> > >> +	if (entity->pads[pad0].flags & MEDIA_PAD_FL_SOURCE
> > >> +	    && entity->pads[pad1].flags & MEDIA_PAD_FL_SINK)
> > >> +		swap(pad0, pad1);
> > >> +
> > >>  	return entity->ops->has_route(entity, pad0, pad1);
> > >>  }
> > >>  EXPORT_SYMBOL_GPL(media_entity_has_route);
>
> --
> Regards,
>
> Laurent Pinchart

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  reply index

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-01 23:31 [PATCH v2 00/30] v4l: add support for multiplexed streams Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 01/30] media: entity: Use pad as a starting point for graph walk Niklas Söderlund
2019-01-15 21:43   ` Laurent Pinchart
2018-11-01 23:31 ` [PATCH v2 02/30] media: entity: Use pads instead of entities in the media graph walk stack Niklas Söderlund
2019-01-15 22:03   ` Laurent Pinchart
2019-01-15 22:13     ` Sakari Ailus
2019-01-15 22:07   ` Laurent Pinchart
2018-11-01 23:31 ` [PATCH v2 03/30] media: entity: Walk the graph based on pads Niklas Söderlund
2019-01-15 22:21   ` Laurent Pinchart
     [not found]     ` <20190115223406.mxgzl36cp54gb7nv@kekkonen.localdomain>
2019-01-15 23:28       ` Laurent Pinchart
2019-01-22 14:50         ` Sakari Ailus
2019-02-14 15:15   ` Jacopo Mondi
2018-11-01 23:31 ` [PATCH v2 04/30] v4l: mc: Start walk from a specific pad in use count calculation Niklas Söderlund
2019-01-15 22:24   ` Laurent Pinchart
2019-01-15 22:36     ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 05/30] media: entity: Move the pipeline from entity to pads Niklas Söderlund
2019-01-15 22:38   ` Laurent Pinchart
2019-01-15 22:48     ` Sakari Ailus
2019-02-14 15:53   ` Jacopo Mondi
2018-11-01 23:31 ` [PATCH v2 06/30] media: entity: Use pad as the starting point for a pipeline Niklas Söderlund
2019-01-15 22:54   ` Laurent Pinchart
2019-01-22 15:31     ` Sakari Ailus
2019-01-22 15:37       ` Laurent Pinchart
2019-01-22 16:16         ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 07/30] media: entity: Add has_route entity operation Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 08/30] media: entity: Add media_has_route() function Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 09/30] media: entity: Swap pads if route is checked from source to sink Niklas Söderlund
2019-01-15 22:57   ` Laurent Pinchart
2019-01-22 15:15     ` Sakari Ailus
2019-01-22 15:20       ` Laurent Pinchart
2019-02-18  9:21         ` Jacopo Mondi [this message]
2019-02-22 12:18           ` Laurent Pinchart
2019-03-04 12:35             ` Jacopo Mondi
2019-03-05 20:04               ` Laurent Pinchart
2019-03-06  8:29                 ` Jacopo Mondi
2018-11-01 23:31 ` [PATCH v2 10/30] media: entity: Use routing information during graph traversal Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 11/30] media: entity: Skip link validation for pads to which there is no route to Niklas Söderlund
2019-01-15 23:13   ` Laurent Pinchart
2018-11-01 23:31 ` [PATCH v2 12/30] media: entity: Add an iterator helper for connected pads Niklas Söderlund
2019-01-15 23:24   ` Laurent Pinchart
2019-01-22 15:36     ` Sakari Ailus
2019-01-22 15:38       ` Laurent Pinchart
2019-01-22 16:21         ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 13/30] media: entity: Add only connected pads to the pipeline Niklas Söderlund
2019-01-15 23:33   ` Laurent Pinchart
2018-11-01 23:31 ` [PATCH v2 14/30] media: entity: Add debug information in graph walk route check Niklas Söderlund
2019-01-15 23:35   ` Laurent Pinchart
2019-01-22 15:38     ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 15/30] media: entity: Look for indirect routes Niklas Söderlund
2019-01-15 23:41   ` Laurent Pinchart
2019-01-22 15:56     ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 16/30] v4l: subdev: Add [GS]_ROUTING subdev ioctls and operations Niklas Söderlund
2019-01-15 23:51   ` Laurent Pinchart
2019-01-22 16:14     ` Sakari Ailus
2019-01-22 17:00       ` Laurent Pinchart
2019-02-21 14:59     ` Jacopo Mondi
2019-02-21 23:49       ` Sakari Ailus
2019-02-22  8:46         ` Jacopo Mondi
2019-02-21 14:39   ` Jacopo Mondi
2019-02-21 22:31     ` Sakari Ailus
2019-02-22  8:40       ` Jacopo Mondi
2019-02-22 11:04         ` Sakari Ailus
2019-02-22 11:17           ` Jacopo Mondi
2019-02-22 11:29             ` Sakari Ailus
2019-02-22 13:37               ` Ian Arkver
2019-02-22 13:50               ` Geert Uytterhoeven
2018-11-01 23:31 ` [PATCH v2 17/30] v4l: subdev: compat: Implement handling for VIDIOC_SUBDEV_[GS]_ROUTING Niklas Söderlund
2019-01-08 10:04   ` Geert Uytterhoeven
2019-01-15 23:53   ` Laurent Pinchart
2019-01-22 15:57     ` Sakari Ailus
2019-02-18 11:21     ` Jacopo Mondi
2019-02-21 23:50       ` Sakari Ailus
2018-11-01 23:31 ` [PATCH v2 18/30] v4l: subdev: Take routing information into account in link validation Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 19/30] v4l: subdev: Improve link format validation debug messages Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 20/30] v4l: mc: Add an S_ROUTING helper function for power state changes Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 21/30] v4l: Add bus type to frame descriptors Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 22/30] v4l: Add CSI-2 bus configuration " Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 23/30] v4l: Add stream to frame descriptor Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 24/30] adv748x: csi2: add translation from pixelcode to CSI-2 datatype Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 25/30] adv748x: csi2: only allow formats on sink pads Niklas Söderlund
2019-02-21 14:18   ` Jacopo Mondi
2018-11-01 23:31 ` [PATCH v2 26/30] adv748x: csi2: describe the multiplexed stream Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 27/30] adv748x: csi2: add internal routing configuration Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 28/30] adv748x: afe: add routing support Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 29/30] rcar-csi2: use frame description information to configure CSI-2 bus Niklas Söderlund
2018-11-01 23:31 ` [PATCH v2 30/30] rcar-csi2: expose the subdevice internal routing Niklas Söderlund
2018-11-14 13:10   ` Nikita Yushchenko
2018-11-14 19:45     ` Niklas Söderlund
2018-12-03 22:16 ` [PATCH v2 00/30] v4l: add support for multiplexed streams Sakari Ailus
2018-12-05 22:09   ` Niklas Söderlund

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