Message-ID: <3de70e29-8429-1b56-8a01-84ca49f4fd89@xs4all.nl>
Date:   Mon, 29 May 2017 17:24:51 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Philipp Zabel <p.zabel@...gutronix.de>
Cc:     Steve Longerbeam <slongerbeam@...il.com>, robh+dt@...nel.org,
        mark.rutland@....com, shawnguo@...nel.org, kernel@...gutronix.de,
        fabio.estevam@....com, linux@...linux.org.uk, mchehab@...nel.org,
        nick@...anahar.org, markus.heiser@...marIT.de,
        laurent.pinchart+renesas@...asonboard.com, bparrot@...com,
        geert@...ux-m68k.org, arnd@...db.de, sudipm.mukherjee@...il.com,
        minghsiu.tsai@...iatek.com, tiffany.lin@...iatek.com,
        jean-christophe.trotin@...com, horms+renesas@...ge.net.au,
        niklas.soderlund+renesas@...natech.se, robert.jarzmik@...e.fr,
        songjun.wu@...rochip.com, andrew-ct.chen@...iatek.com,
        gregkh@...uxfoundation.org, shuah@...nel.org,
        sakari.ailus@...ux.intel.com, pavel@....cz,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org,
        devel@...verdev.osuosl.org,
        Steve Longerbeam <steve_longerbeam@...tor.com>
Subject: Re: [PATCH v7 00/34] i.MX Media Driver

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

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