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

From: Hans Verkuil
Date: Mon May 29 2017 - 11:25:03 EST


On 05/29/2017 04:21 PM, Hans Verkuil wrote:
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.

Thanks for those updates! That really leaves just an Ack for patch 2/34.

Sooo close!

Regards,

Hans