Re: [PATCH v7 00/34] i.MX Media Driver

[Hans Verkuil]

On 05/29/2017 04:15 PM, Philipp Zabel wrote:
> On Mon, 2017-05-29 at 15:46 +0200, Hans Verkuil wrote:
> > Hi Steve,
> >
> > On 05/25/2017 02:29 AM, Steve Longerbeam wrote:
> > > In version 7:
> > >
> > > - video-mux: switched to Philipp's latest video-mux driver and updated
> > >     bindings docs, that makes use of the mmio-mux framework.
> > >
> > > - mmio-mux: includes Philipp's temporary patch that adds mmio-mux support
> > >     to video-mux driver, until mux framework is merged.
> > >
> > > - mmio-mux: updates to device tree from Philipp that define the i.MX6 mux
> > >     devices and modifies the video-mux device to become a consumer of the
> > >     video mmio-mux.
> > >
> > > - minor updates to Documentation/media/v4l-drivers/imx.rst.
> > >
> > > - ov5640: do nothing if entity stream count is greater than 1 in
> > >     ov5640_s_stream().
> > >
> > > - Previous versions of this driver had not tested the ability to enable
> > >     multiple independent streams, for instance enabling multiple output
> > >     pads from the imx6-mipi-csi2 subdevice, or enabling both prpenc and
> > >     prpvf outputs. Marek Vasut tested this support and reported issues
> > >     with it.
> > >
> > >     v4l2_pipeline_inherit_controls() used the media graph walk APIs, but
> > >     that walks both sink and source pads, so if there are multiple paths
> > >     enabled to video capture devices, controls would be added to the wrong
> > >     video capture device, and no controls added to the other enabled
> > >     capture devices.
> > >
> > >     These issues have been fixed. Control inheritance works correctly now
> > >     even with multiple enabled capture paths, and (for example)
> > >     simultaneous capture from prpenc and prpvf works also, and each with
> > >     independent scaling, CSC, and controls. For example prpenc can be
> > >     capturing with a 90 degree rotation, while prpvf is capturing with
> > >     vertical flip.
> > >
> > >     So the v4l2_pipeline_inherit_controls() patch has been dropped. The
> > >     new version of control inheritance could be made generically available,
> > >     but it would be more involved to incorporate it into v4l2-core.
> > >
> > > - A new function imx_media_fill_default_mbus_fields() is added to setup
> > >     colorimetry at sink pads, and these are propagated to source pads.
> > >
> > > - Ensure that the current sink and source rectangles meet alignment
> > >     restrictions before applying a new rotation control setting in
> > >     prp-enc/vf subdevices.
> > >
> > > - Chain the s_stream() subdev calls instead of implementing a custom
> > >     stream on/off function that attempts to call a fixed set of subdevices
> > >     in a pipeline in the correct order. This also simplifies imx6-mipi-csi2
> > >     subdevice, since the correct MIPI CSI-2 startup sequence can be
> > >     enforced completely in s_stream(), and s_power() is no longer
> > >     required. This also paves the way for more arbitrary OF graphs
> > >     external to the i.MX6.
> > >
> > > - Converted the v4l2_subdev and media_entity ops structures to const.
> >
> > What is the status as of v7?
> >
> >   From what I can tell patch 2/34 needs an Ack from Rob Herring, patches
> > 4-14 are out of scope for the media subsystem, patches 20-25 and 27-34
> > are all staging (so fine to be merged from my point of view).
> >
> > I'm not sure if patch 26 (defconfig) should be applied while the imx
> > driver is in staging. I would suggest that this patch is moved to the end
> > of the series.
> >
> > That leaves patches 15-19. I replied to patch 15 with a comment, patches
> > 16-18 look good to me, although patches 17 and 18 should be combined to one
> > patch since patch 17 won't compile otherwise.
>
> Is this a problem? It won't break any builds as patch 17 depends on
> CONFIG_MULTIPLEXER, which doesn't exist yet. I'm fine with merging the
> two patches, though.

You are right, but it is weird. I think I would prefer to have these two
merged and the #ifdef CONFIG_MULTIPLEXER bits removed. Just a note in the
commit log that this should be converted to the multiplexer when that gets
merged would be enough.

Dead code in drivers/media should be avoided because that's what this
driver currently has.

Regards,

	Hans

> > Any idea when the multiplexer is expected to be merged? (just curious)
>
> I have no idea. v15 of the multiplexer framework patchset was posted on
> 2017-05-14, is still waiting for comments.
>
> > I would really like to get this merged for 4.13, so did I miss anything?
>
> Seconded, and not that I can tell.
>
> >   From what I can tell it is really just an Ack for patch 2/34.
>
> regards
> Philipp