soc-camera: opinion poll - future directions

soc-camera: opinion poll - future directions

[Guennadi Liakhovetski]

Hi all,

Just a quick opinion poll - where and how should the soc-camera framework 
and drivers be heading? Possible (probably not all) directions:

(1) all is good, keep as is. That means keep all drivers, killing them off 
only when it becomes very obvious, that noone wants them, keep developing 
drivers, that are still being used and updating all of them on any API 
updates. Keep me as maintainer, which means slow patch processing rate and 
no active participation in new developments - at hardware, soc-camera or 
V4L levels.

(2) we want more! I.e. some contributors are planning to either add new 
drivers to it or significantly develop existing ones, see significant 
benefit in it. In this case it might become necessary to replace me with 
someone, who can be more active in this area.

(3) slowly phase out. Try to either deprecate and remove soc-camera 
drivers one by one or move them out to become independent V4L2 host or 
subdevice drivers, but keep updating while still there.

(4) basically as (3) but even more aggressively - get rid of it ASAP:)

Opinions? Expecially would be interesting to hear from respective 
host-driver maintainers / developers, sorry, not adding CCs, they probably 
read the list anyway:)

Thanks
Guennadi

Re: soc-camera: opinion poll - future directions

[Hans Verkuil]

Hi Guennadi,

On 05/03/2015 06:11 PM, Guennadi Liakhovetski wrote:
> Hi all,
> 
> Just a quick opinion poll - where and how should the soc-camera framework 
> and drivers be heading? Possible (probably not all) directions:
> 
> (1) all is good, keep as is. That means keep all drivers, killing them off 
> only when it becomes very obvious, that noone wants them, keep developing 
> drivers, that are still being used and updating all of them on any API 
> updates. Keep me as maintainer, which means slow patch processing rate and 
> no active participation in new developments - at hardware, soc-camera or 
> V4L levels.
> 
> (2) we want more! I.e. some contributors are planning to either add new 
> drivers to it or significantly develop existing ones, see significant 
> benefit in it. In this case it might become necessary to replace me with 
> someone, who can be more active in this area.
> 
> (3) slowly phase out. Try to either deprecate and remove soc-camera 
> drivers one by one or move them out to become independent V4L2 host or 
> subdevice drivers, but keep updating while still there.
> 
> (4) basically as (3) but even more aggressively - get rid of it ASAP:)
> 
> Opinions? Expecially would be interesting to hear from respective 
> host-driver maintainers / developers, sorry, not adding CCs, they probably 
> read the list anyway:)

I'm closest to 1. I would certainly not use it for new drivers, I see no
reason to do that anymore. The core frameworks are quite good these days
and I think the need for soc-camera has basically disappeared. But there
is no need to phase out or remove soc-camera drivers (unless they are
clearly broken and nobody will fix them). And if someone wants to turn
a soc-camera driver into a standalone driver, then I would encourage
that.

However, there are two things that need work fairly soon:

1) the dependency of subdev drivers on soc_camera: that has to go. I plan
to work on that, but the first step is to replace the video crop ops by
the pad selection ops. I finally got my Renesas sh7724 board up and running,
so I hope to make progress on this soon. I'll update soc-camera as well
to conform to v4l2-compliance. Once that's done I will investigate how to
remove the soc-camera dependency.

The soc-camera dependency kills the reusability of those drivers and it
really needs to be addressed.

2) Converting soc-camera videobuf drivers to vb2. At some point vb1 will be
removed, so any remaining vb1 driver will likely be killed off if nobody does
the conversion. I believe it is only omap1 and pxa that still use videobuf.

I think omap1 might be a candidate for removal, but I don't know about the pxa.
Guennadi, what is the status of these drivers? If I would do a vb2 conversion
for the pxa, would you be able to test it?

Regards,

	Hans

Re: soc-camera: opinion poll - future directions

[Guennadi Liakhovetski]

Hi Hans,

On Sun, 3 May 2015, Hans Verkuil wrote:

> Hi Guennadi,
> 
> On 05/03/2015 06:11 PM, Guennadi Liakhovetski wrote:
> > Hi all,
> > 
> > Just a quick opinion poll - where and how should the soc-camera framework 
> > and drivers be heading? Possible (probably not all) directions:
> > 
> > (1) all is good, keep as is. That means keep all drivers, killing them off 
> > only when it becomes very obvious, that noone wants them, keep developing 
> > drivers, that are still being used and updating all of them on any API 
> > updates. Keep me as maintainer, which means slow patch processing rate and 
> > no active participation in new developments - at hardware, soc-camera or 
> > V4L levels.
> > 
> > (2) we want more! I.e. some contributors are planning to either add new 
> > drivers to it or significantly develop existing ones, see significant 
> > benefit in it. In this case it might become necessary to replace me with 
> > someone, who can be more active in this area.
> > 
> > (3) slowly phase out. Try to either deprecate and remove soc-camera 
> > drivers one by one or move them out to become independent V4L2 host or 
> > subdevice drivers, but keep updating while still there.
> > 
> > (4) basically as (3) but even more aggressively - get rid of it ASAP:)
> > 
> > Opinions? Expecially would be interesting to hear from respective 
> > host-driver maintainers / developers, sorry, not adding CCs, they probably 
> > read the list anyway:)
> 
> I'm closest to 1. I would certainly not use it for new drivers, I see no
> reason to do that anymore. The core frameworks are quite good these days
> and I think the need for soc-camera has basically disappeared. But there
> is no need to phase out or remove soc-camera drivers (unless they are
> clearly broken and nobody will fix them). And if someone wants to turn
> a soc-camera driver into a standalone driver, then I would encourage
> that.

Understand, thanks.

> However, there are two things that need work fairly soon:
> 
> 1) the dependency of subdev drivers on soc_camera: that has to go. I plan
> to work on that, but the first step is to replace the video crop ops by
> the pad selection ops. I finally got my Renesas sh7724 board up and running,

Uhm... Does anyone really still care about V4L on SuperH?..

> so I hope to make progress on this soon. I'll update soc-camera as well
> to conform to v4l2-compliance. Once that's done I will investigate how to
> remove the soc-camera dependency.
> 
> The soc-camera dependency kills the reusability of those drivers and it
> really needs to be addressed.
> 
> 2) Converting soc-camera videobuf drivers to vb2. At some point vb1 will be
> removed, so any remaining vb1 driver will likely be killed off if nobody does
> the conversion. I believe it is only omap1 and pxa that still use videobuf.
> 
> I think omap1 might be a candidate for removal, but I don't know about the pxa.
> Guennadi, what is the status of these drivers?

Dont know, sorry. PXA in general seems to still be quite actively 
maintained - I recently saw a patch series for PXA CCF support, so, 
probably V4L is still in use too.

> If I would do a vb2 conversion
> for the pxa, would you be able to test it?

I have a board with PXA270, and it still seems to be in the mainline, but 
I don't know how easy it would be to get it running with a current kernel.

Thanks
Guennadi

Re: soc-camera: opinion poll - future directions

[Hans Verkuil]

On 05/03/2015 07:45 PM, Guennadi Liakhovetski wrote:
> Hi Hans,
> 
> On Sun, 3 May 2015, Hans Verkuil wrote:
> 
>> Hi Guennadi,
>>
>> On 05/03/2015 06:11 PM, Guennadi Liakhovetski wrote:
>>> Hi all,
>>>
>>> Just a quick opinion poll - where and how should the soc-camera framework 
>>> and drivers be heading? Possible (probably not all) directions:
>>>
>>> (1) all is good, keep as is. That means keep all drivers, killing them off 
>>> only when it becomes very obvious, that noone wants them, keep developing 
>>> drivers, that are still being used and updating all of them on any API 
>>> updates. Keep me as maintainer, which means slow patch processing rate and 
>>> no active participation in new developments - at hardware, soc-camera or 
>>> V4L levels.
>>>
>>> (2) we want more! I.e. some contributors are planning to either add new 
>>> drivers to it or significantly develop existing ones, see significant 
>>> benefit in it. In this case it might become necessary to replace me with 
>>> someone, who can be more active in this area.
>>>
>>> (3) slowly phase out. Try to either deprecate and remove soc-camera 
>>> drivers one by one or move them out to become independent V4L2 host or 
>>> subdevice drivers, but keep updating while still there.
>>>
>>> (4) basically as (3) but even more aggressively - get rid of it ASAP:)
>>>
>>> Opinions? Expecially would be interesting to hear from respective 
>>> host-driver maintainers / developers, sorry, not adding CCs, they probably 
>>> read the list anyway:)
>>
>> I'm closest to 1. I would certainly not use it for new drivers, I see no
>> reason to do that anymore. The core frameworks are quite good these days
>> and I think the need for soc-camera has basically disappeared. But there
>> is no need to phase out or remove soc-camera drivers (unless they are
>> clearly broken and nobody will fix them). And if someone wants to turn
>> a soc-camera driver into a standalone driver, then I would encourage
>> that.
> 
> Understand, thanks.
> 
>> However, there are two things that need work fairly soon:
>>
>> 1) the dependency of subdev drivers on soc_camera: that has to go. I plan
>> to work on that, but the first step is to replace the video crop ops by
>> the pad selection ops. I finally got my Renesas sh7724 board up and running,
> 
> Uhm... Does anyone really still care about V4L on SuperH?..

I am :-)

It's the only soc-camera board I have, so it's good to have it working.

> 
>> so I hope to make progress on this soon. I'll update soc-camera as well
>> to conform to v4l2-compliance. Once that's done I will investigate how to
>> remove the soc-camera dependency.
>>
>> The soc-camera dependency kills the reusability of those drivers and it
>> really needs to be addressed.
>>
>> 2) Converting soc-camera videobuf drivers to vb2. At some point vb1 will be
>> removed, so any remaining vb1 driver will likely be killed off if nobody does
>> the conversion. I believe it is only omap1 and pxa that still use videobuf.
>>
>> I think omap1 might be a candidate for removal, but I don't know about the pxa.
>> Guennadi, what is the status of these drivers?
> 
> Dont know, sorry. PXA in general seems to still be quite actively 
> maintained - I recently saw a patch series for PXA CCF support, so, 
> probably V4L is still in use too.
> 
>> If I would do a vb2 conversion
>> for the pxa, would you be able to test it?
> 
> I have a board with PXA270, and it still seems to be in the mainline, but 
> I don't know how easy it would be to get it running with a current kernel.

Can you take a look? If you can get it running, then I can make a patch for
you to try. But I don't want to put time into that unless I know you can
test it.

I think it is reasonable to phase out the omap1 driver: move it to staging
first and if nobody complains remove it altogether.

Regards,

	Hans

Re: soc-camera: opinion poll - future directions

[Vaibhav Hiremath]

On Monday 04 May 2015 12:49 PM, Hans Verkuil wrote:
> On 05/03/2015 07:45 PM, Guennadi Liakhovetski wrote:
>> Hi Hans,
>>
>> On Sun, 3 May 2015, Hans Verkuil wrote:
>>
>>> Hi Guennadi,
>>>
>>> On 05/03/2015 06:11 PM, Guennadi Liakhovetski wrote:
>>>> Hi all,
>>>>
>>>> Just a quick opinion poll - where and how should the soc-camera framework
>>>> and drivers be heading? Possible (probably not all) directions:
>>>>
>>>> (1) all is good, keep as is. That means keep all drivers, killing them off
>>>> only when it becomes very obvious, that noone wants them, keep developing
>>>> drivers, that are still being used and updating all of them on any API
>>>> updates. Keep me as maintainer, which means slow patch processing rate and
>>>> no active participation in new developments - at hardware, soc-camera or
>>>> V4L levels.
>>>>
>>>> (2) we want more! I.e. some contributors are planning to either add new
>>>> drivers to it or significantly develop existing ones, see significant
>>>> benefit in it. In this case it might become necessary to replace me with
>>>> someone, who can be more active in this area.
>>>>
>>>> (3) slowly phase out. Try to either deprecate and remove soc-camera
>>>> drivers one by one or move them out to become independent V4L2 host or
>>>> subdevice drivers, but keep updating while still there.
>>>>
>>>> (4) basically as (3) but even more aggressively - get rid of it ASAP:)
>>>>
>>>> Opinions? Expecially would be interesting to hear from respective
>>>> host-driver maintainers / developers, sorry, not adding CCs, they probably
>>>> read the list anyway:)
>>>
>>> I'm closest to 1. I would certainly not use it for new drivers, I see no
>>> reason to do that anymore. The core frameworks are quite good these days
>>> and I think the need for soc-camera has basically disappeared. But there
>>> is no need to phase out or remove soc-camera drivers (unless they are
>>> clearly broken and nobody will fix them). And if someone wants to turn
>>> a soc-camera driver into a standalone driver, then I would encourage
>>> that.
>>
>> Understand, thanks.
>>
>>> However, there are two things that need work fairly soon:
>>>
>>> 1) the dependency of subdev drivers on soc_camera: that has to go. I plan
>>> to work on that, but the first step is to replace the video crop ops by
>>> the pad selection ops. I finally got my Renesas sh7724 board up and running,
>>
>> Uhm... Does anyone really still care about V4L on SuperH?..
>
> I am :-)
>
> It's the only soc-camera board I have, so it's good to have it working.
>
>>
>>> so I hope to make progress on this soon. I'll update soc-camera as well
>>> to conform to v4l2-compliance. Once that's done I will investigate how to
>>> remove the soc-camera dependency.
>>>
>>> The soc-camera dependency kills the reusability of those drivers and it
>>> really needs to be addressed.
>>>
>>> 2) Converting soc-camera videobuf drivers to vb2. At some point vb1 will be
>>> removed, so any remaining vb1 driver will likely be killed off if nobody does
>>> the conversion. I believe it is only omap1 and pxa that still use videobuf.
>>>
>>> I think omap1 might be a candidate for removal, but I don't know about the pxa.
>>> Guennadi, what is the status of these drivers?
>>
>> Dont know, sorry. PXA in general seems to still be quite actively
>> maintained - I recently saw a patch series for PXA CCF support, so,
>> probably V4L is still in use too.
>>
>>> If I would do a vb2 conversion
>>> for the pxa, would you be able to test it?
>>
>> I have a board with PXA270, and it still seems to be in the mainline, but
>> I don't know how easy it would be to get it running with a current kernel.
>
> Can you take a look? If you can get it running, then I can make a patch for
> you to try. But I don't want to put time into that unless I know you can
> test it.
>
> I think it is reasonable to phase out the omap1 driver: move it to staging
> first and if nobody complains remove it altogether.
>

Hans,

I think OMAP2_VOUT is also another candidate which we need to probably
move it to staging and then remove it.
I am not sure if anyone is still using it.

It is just compiling as of now, but I am doubtful that it will work.


Thanks,
Vaibhav