Date:   Fri, 29 Apr 2022 10:33:47 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Eugen.Hristev@...rochip.com, linux-media@...r.kernel.org,
        jacopo@...ndi.org
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, Claudiu.Beznea@...rochip.com,
        robh+dt@...nel.org, Nicolas.Ferre@...rochip.com
Subject: Re: [PATCH v9 00/13] media: atmel: atmel-isc: implement media
 controller

On 29/04/2022 10:20, Eugen.Hristev@...rochip.com wrote:
> On 4/29/22 11:05 AM, Hans Verkuil wrote:
>> Hi Eugen,
>>
>> On 10/03/2022 10:51, Eugen Hristev wrote:
>>> This series is the v9 series that attempts to support media controller in the
>>> atmel ISC and XISC drivers.
>>> The CSI2DC driver was accepted thus removed from the patch series, together with
>>> other patches.
>>>
>>> Important note: this series applies on top of current media_staging tree, as it
>>> relies on previous patches in the series which were accepted.
>>>
>>> Thanks to everyone who reviewed my work !
>>>
>>> Eugen
>>>
>>> Changes in v9:
>>> -> kernel robot reported isc_link_validate is not static, changed to static.
>>>
>>> Changes in v8:
>>> -> scaler: modified crop bounds to have the exact source size
>>>
>>> Changes in v7:
>>> -> scaler: modified crop bounds to have maximum isc size
>>> -> format propagation: did small changes as per Jacopo review
>>>
>>>
>>> Changes in v6:
>>> -> worked a bit on scaler, added try crop and other changes as per Jacopo review
>>> -> worked on isc-base enum_fmt , reworked as per Jacopo review
>>>
>>> Changes in v5:
>>> -> removed patch that removed the 'stop' variable as it was still required
>>> -> added two new trivial patches
>>> -> reworked some parts of the scaler and format propagation after discussions with Jacopo
>>>
>>>
>>> Changes in v4:
>>> -> as reviewed by Hans, added new patch to remove the 'stop' variable and reworked
>>> one patch that was using it
>>> -> as reviewed by Jacopo, reworked some parts of the media controller implementation
>>>
>>>
>>> Changes in v3:
>>> - change in bindings, small fixes in csi2dc driver and conversion to mc
>>> for the isc-base.
>>> - removed some MAINTAINERS patches and used patterns in MAINTAINERS
>>>
>>> Changes in v2:
>>> - integrated many changes suggested by Jacopo in the review of the v1 series.
>>> - add a few new patches
>>>
>>>
>>>
>>> Eugen Hristev (13):
>>>    media: atmel: atmel-isc-base: use streaming status when queueing
>>>      buffers
>>>    media: atmel: atmel-isc-base: replace is_streaming call in
>>>      s_fmt_vid_cap
>>>    media: atmel: atmel-isc: remove redundant comments
>>>    media: atmel: atmel-isc: implement media controller
>>>    media: atmel: atmel-sama5d2-isc: fix wrong mask in YUYV format check
>>>    media: atmel: atmel-isc-base: use mutex to lock awb workqueue from
>>>      streaming
>>>    media: atmel: atmel-isc: compact the controller formats list
>>>    media: atmel: atmel-isc: change format propagation to subdev into only
>>>      verification
>>>    media: atmel: atmel-sama7g5-isc: remove stray line
>>>    dt-bindings: media: microchip,xisc: add bus-width of 14
>>
>> I'm a bit unhappy with the order of these patches. Mostly these are fixes,
>> except for patches 4 and 8, which are the meat of this series and actually
>> switching on the MC support.
>>
>> Can those be moved to the end? That also makes it easier to merge the earlier
>> patches if some more work is needed for the MC part.
>>
>> I'm also not sure whether patches 4 and 8 shouldn't be a single patch,
>> since patch 4 leaves the driver in an inconsistent state since it is
>> missing the link validation code that patch 8 adds. Unless I missed
>> something?
> 
> Hello Hans,
> 
> The difference that patch 8 is making is that the 'old way' of 
> configuring the ISC is no longer possible.
> 
> Patch 4 makes the ISC 'mc-ready' with all entities, links, but the old 
> way still works (meaning that the top driver will call s_fmt down to the 
> subdev ).
> After patch 8, the driver no longer has this support at all, and 
> validates links at start_streaming, and no longer sets anything to the 
> subdev, just validates the config that the subdev already has.
> So one reason that I had things in two patches was that patch 8 makes 
> this big change that also makes userspace behave differently and has to 
> configure all the subdevs and media pipeline.
> 
> If you feel patch 4 and patch 8 should be squashed, I can do it, definitely.
> 
> Let me know how to proceed ?

Ah, that was your intention. The problem in patch 4 is that you set
V4L2_CAP_IO_MC, which indicates to applications that they have to use
the MC and configure the pipeline correctly. Moving that to patch 8
should resolve that, I think.

Regards,

	Hans

> 
> Thanks,
> Eugen
> 
>>
>> Regards,
>>
>>          Hans
>>
>>>    ARM: dts: at91: sama7g5: add nodes for video capture
>>>    ARM: configs: at91: sama7: add xisc and csi2dc
>>>    ARM: multi_v7_defconfig: add atmel video pipeline modules
>>>
>>>   .../bindings/media/microchip,xisc.yaml        |   2 +-
>>>   arch/arm/boot/dts/sama7g5.dtsi                |  49 ++
>>>   arch/arm/configs/multi_v7_defconfig           |   3 +
>>>   arch/arm/configs/sama7_defconfig              |   2 +
>>>   drivers/media/platform/atmel/Makefile         |   2 +-
>>>   drivers/media/platform/atmel/atmel-isc-base.c | 518 ++++++++++--------
>>>   .../media/platform/atmel/atmel-isc-scaler.c   | 267 +++++++++
>>>   drivers/media/platform/atmel/atmel-isc.h      |  58 +-
>>>   .../media/platform/atmel/atmel-sama5d2-isc.c  |  87 +--
>>>   .../media/platform/atmel/atmel-sama7g5-isc.c  |  93 ++--
>>>   10 files changed, 754 insertions(+), 327 deletions(-)
>>>   create mode 100644 drivers/media/platform/atmel/atmel-isc-scaler.c
>>>
>>
> 

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