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

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

Em 04-03-2011 19:49, David Cohen escreveu:
> On Sat, Mar 5, 2011 at 12:43 AM, Mauro Carvalho Chehab
> <mchehab@redhat.com> wrote:
>> 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.
> 
> Ok. I'll provide a patch for it.

Ok, thanks.
> 
>>
>>>>        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?
> 
> Currently the driver does not support such situation. Either all
> modules successfully initialize or ISP driver doesn't probe correctly.

I'm not sure if I understood (or if you understood my question ;) )

What I'm asking is: what happens if the private ioctl's for CCDC and Preview
initialization are never called (or any other private/subdev ioctl)? 
The device will work or not?

Cheers,
Mauro