Re: [PATCH v3 00/32] Separate links and async sub-devices

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Hi Philipp,

On Wed, May 24, 2023 at 02:58:08PM +0200, Philipp Zabel wrote:
> Hi Sakari,
> 
> On Mi, 2023-05-24 at 14:23 +0300, Sakari Ailus wrote:
> > Hi all,
> > 
> > This set adds support for multiple downstream links in an async
> > sub-device, by separating the sub-device registration from the link
> > creation.
> > 
> > A new concept, V4L2 async connection is added. A connection later on
> > translates to an MC ancillary or data link. Generally async notifiers have
> > a number of connections but at that level there is no knowledge of how
> > many sub-devices they will connect to. The bound and unbound callbacks now
> > work on connections. For the existing drivers there's only one connection
> > so I do not expect regressions because of that.
> > 
> > Async sub-device fwnode matching will now take place between the device
> > (the dev field of struct v4l2_subdev) and a struct v4l2_async_connection
> > (an endpoint for devices that have endpoints or the device for those that
> > do not). This is because the graph data structure only describes
> > point-to-point connections so therefore defining one end of the connection
> > defines the entire connection.
> > 
> > This set is unlikely to address all needs people have related to the async
> > framework but I think that beyond what it does, it paves some way for
> > addressing more of those additional needs.
> > 
> > To be frank, I'd like to get rid of the entire V4L2 async framework, but
> > it would require allowing much more dynamic driver initialisation,
> > including sub-devices and device nodes popping up in the system in the
> > order and extent there is successfully probed hardware. Until that, and
> > this may well be the entire foreseeable future, we have at least some of
> > this complexity.
> > 
> > I didn't add the Tested-by: tags I got for v2 as there are significant
> > changes, albeit only for better I hope. :-) Niklas has also tested this on
> > rcar-vin + adv746x, it works now while on v2 it did not. So having also
> > this version validated on i.MX6 would be nice.
> 
> Still works on i.MX6QP with TC358743.
> 
> Tested-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> # imx6qp

Thanks a lot for testing again!

-- 
Regards,

Sakari Ailus



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