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, 4 Mar 2019 13:35:36 +0100 [thread overview]
Message-ID: <20190304123520.et24vsesfulyzybs@uno.localdomain> (raw)
In-Reply-To: <20190222121811.GU3522@pendragon.ideasonboard.com>
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Hi Laurent,
On Fri, Feb 22, 2019 at 02:18:11PM +0200, Laurent Pinchart wrote:
> Hi Jacopo,
>
> On Mon, Feb 18, 2019 at 10:21:07AM +0100, Jacopo Mondi wrote:
> > On Tue, Jan 22, 2019 at 05:20:30PM +0200, Laurent Pinchart wrote:
> > > 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?
>
> I fear this will be confusing for subdevs, as they would have to
> implement part of the operation.
>
> Could it be that the subdev has_route operation isn't the best API for
> the job, if it gets that complex ? I wonder if it would be easier to
> create another operation that takes a pad index as argument, and returns
> the list of pads (possibly as a bitmask ?) or connected pads.
> media_entity_has_route() could easily be implemented on top of that, and
> these new semantics may be easier for subdevs to implement.
>
I see, but if subdevs can easily elaborate that list, they could as
well easily check if the pad provided as argument is on that list.
> > >>> 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?
>
> I think that's the worst of both worlds from a subdev point of view :-)
>
Possibly :)
Should we drop completely the sink-source ordering in favour of
ordering by value, and drop [15/30] that adds support for trivial
indirect routes?
Let's reach consensus so I could send v3.
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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next prev parent reply other threads:[~2019-03-04 12:35 UTC|newest]
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
2019-02-22 12:18 ` Laurent Pinchart
2019-03-04 12:35 ` Jacopo Mondi [this message]
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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