Re: [GIT PULL FOR 2.6.39] Media controller and OMAP3 ISP driver

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em 04-03-2011 19:33, David Cohen escreveu:
> Hi Mauro,
> 
> On Sat, Mar 5, 2011 at 12:16 AM, Mauro Carvalho Chehab
> <mchehab@redhat.com> wrote:
>> Hi Laurent,
>>
>> Em 17-02-2011 13:06, Laurent Pinchart escreveu:
>>> Hi Mauro,
>>>
>>> The following changes since commit 85e2efbb1db9a18d218006706d6e4fbeb0216213:
>>>
>>>   Linux 2.6.38-rc5 (2011-02-15 19:23:45 -0800)
>>>
>>> are available in the git repository at:
>>>   git://linuxtv.org/pinchartl/media.git media-0005-omap3isp
>>
>> I've added the patches that looked ok on my eyes at:
>>
>> http://git.linuxtv.org/mchehab/experimental.git?a=shortlog;h=refs/heads/media_controller
>>
>> There are just a few small adjustments on a few of them, as I've commented.
>> I prefer if you do them on separate patches, to save my work of not needing
>> to review the entire series again.
>>
>> The ones still pending on my quilt tree are:
>>
>> 0030-v4l-subdev-Generic-ioctl-support.patch
>> 0040-omap3isp-OMAP3-ISP-core.patch
>> 0041-omap3isp-Video-devices-and-buffers-queue.patch
>> 0042-omap3isp-CCP2-CSI2-receivers.patch
>> 0043-omap3isp-CCDC-preview-engine-and-resizer.patch
>> 0044-omap3isp-Statistics.patch
>> 0045-omap3isp-Kconfig-and-Makefile.patch
>> 0046-omap3isp-Add-set-performance-callback-in-isp-platfor.patch
>>
>> with the following diffstat:
>>
>>  Documentation/video4linux/v4l2-framework.txt       |    5 +
>>  MAINTAINERS                                        |    6 +
>>  drivers/media/video/Kconfig                        |   13 +
>>  drivers/media/video/Makefile                       |    2 +
>>  drivers/media/video/omap3-isp/Makefile             |   13 +
>>  drivers/media/video/omap3-isp/cfa_coef_table.h     |   61 +
>>  drivers/media/video/omap3-isp/gamma_table.h        |   90 +
>>  drivers/media/video/omap3-isp/isp.c                | 2220 +++++++++++++++++++
>>  drivers/media/video/omap3-isp/isp.h                |  428 ++++
>>  drivers/media/video/omap3-isp/ispccdc.c            | 2268 ++++++++++++++++++++
>>  drivers/media/video/omap3-isp/ispccdc.h            |  219 ++
>>  drivers/media/video/omap3-isp/ispccp2.c            | 1173 ++++++++++
>>  drivers/media/video/omap3-isp/ispccp2.h            |   98 +
>>  drivers/media/video/omap3-isp/ispcsi2.c            | 1317 ++++++++++++
>>  drivers/media/video/omap3-isp/ispcsi2.h            |  166 ++
>>  drivers/media/video/omap3-isp/ispcsiphy.c          |  247 +++
>>  drivers/media/video/omap3-isp/ispcsiphy.h          |   74 +
>>  drivers/media/video/omap3-isp/isph3a.h             |  117 +
>>  drivers/media/video/omap3-isp/isph3a_aewb.c        |  374 ++++
>>  drivers/media/video/omap3-isp/isph3a_af.c          |  429 ++++
>>  drivers/media/video/omap3-isp/isphist.c            |  520 +++++
>>  drivers/media/video/omap3-isp/isphist.h            |   40 +
>>  drivers/media/video/omap3-isp/isppreview.c         | 2113 ++++++++++++++++++
>>  drivers/media/video/omap3-isp/isppreview.h         |  214 ++
>>  drivers/media/video/omap3-isp/ispqueue.c           | 1153 ++++++++++
>>  drivers/media/video/omap3-isp/ispqueue.h           |  187 ++
>>  drivers/media/video/omap3-isp/ispreg.h             | 1589 ++++++++++++++
>>  drivers/media/video/omap3-isp/ispresizer.c         | 1693 +++++++++++++++
>>  drivers/media/video/omap3-isp/ispresizer.h         |  147 ++
>>  drivers/media/video/omap3-isp/ispstat.c            | 1092 ++++++++++
>>  drivers/media/video/omap3-isp/ispstat.h            |  169 ++
>>  drivers/media/video/omap3-isp/ispvideo.c           | 1255 +++++++++++
>>  drivers/media/video/omap3-isp/ispvideo.h           |  202 ++
>>  drivers/media/video/omap3-isp/luma_enhance_table.h |   42 +
>>  drivers/media/video/omap3-isp/noise_filter_table.h |   30 +
>>  drivers/media/video/v4l2-subdev.c                  |    2 +-
>>  drivers/media/video/videobuf-dma-contig.c          |    2 +-
>>  include/linux/Kbuild                               |    1 +
>>  38 files changed, 19769 insertions(+), 2 deletions(-)
>>
>> I used quilt for all patches, except for the one patch with some gifs, where I did a
>> git cherry-pick. So, the imported patches should be ok. Of course, it doesn't hurt
>> do double check.
>>
>> The main issue with the omap3isp is due to the presence of private ioctl's that
>> I don't have a clear idea about what they are really doing.
>>
>> I couldn't see any documentation about them on a very quick look. While I suspect
>> that they are used only for 3A, I have no means of being sure about that.
>>
>> Also, as I've said several times, while I don't like, I have nothing against
>> having some ioctls that would be used by a vendor to implement their own 3A software
>> algorithms that he may need to hide for some reason or have any patents applied to
>> the algorithm, but only if:
>>        1) such algorithms are implemented on userspace;
> 
> Yes.
> 
>>        2) the userspace API used by them is fully documented, in order
>> to allow that someone else with enough motivation and spare time may
>> want to implement his own algorithm (including an open-source one);
> 
> The API is pretty close to what is found on public OMAP3 TRM. I'd say
> it's almost to fill registers through a userspace API.

Ok, so a simple patch adding a txt file documenting those private ioctls
to Documentation/video4linux explaining how to use them and pointing to 
OMAP3 TRM documentation is enough.

>>        3) there are no patents denying or charging for the usage and/or
>> distribution/redistribution of the Kernel with the provided kernel driver;
> 
> I'd say there's no patent / charge for usage or redistribution. But
> that's lawyer stuff. :/
> 
>>        4) if the device works with a reasonable quality without them
>> (by reasonable I mean like a cheap webcam, where libv4l could use his
>> set of 3A algorithms to provide a good quality).
> 
> It depends on the sensor as well, but in general should work with a
> reasonable quality without using statistic modules.
> 
>>
>> Assuming that all those private ioctl's are really for 3A, it is ok for me
>> to accept such ioctls after being sure that the above applies. I'm not sure
>> how to check (4), as, while I have 2 omap boards here (a Beagleboard and a
>> gumstix), none of them have any sensor.
> 
> The private ioctl are used mostly on statistic modules (3A and
> Histogram). But it's used for CCDC and Preview modules configuration
> too.

The issue here is: what if no CCDC and no Preview initialization ever happen?

Cheers,
Mauro