> Thanks Guennadi for your quick response ,
>
> >Hi Alex
>
> > Hi Guennadi,
> >
> > We would like to use I.MX35 processor in new project.
> > An important element of the project is to obtain life video from the camera
> > and display it on display.
> > For these purposes, we want to use mainline Linux kernel which supports all
> > the necessary drivers for the implementation of this task.
> > As I understand that soc_camera is not currently supported userptr method,
> > in which case how I can configure the video pipeline in user space
> > to get the live video on display, without the intervention of the processor.
>
> >soc-camera does support USERPTR, also the mx3_camera driver claims to
> >support it.
>
> I based on soc-camera.txt document.
> Yeah, I really have to update it...
> The soc-camera subsystem provides a unified API between camera host drivers
> and
> camera sensor drivers. It implements a V4L2 interface to the user, currently
> only the mmap method is supported.
>
> In any case, I glad that this supported :-)
>
> What do you think it is possible to implement video streaming without
> the intervention of the processor?
>It might be difficult to completely eliminate the CPU, at the very least
>you need to queue and dequeue buffers to and from the V4L driver. To avoid
>even that, in principle, you could try to use only one buffer, but I don't
>think the current version of the mx3_camera driver would be very happy
>about that. You could take 2 buffers and use panning, then you'd just have
>to send queue and dequeue buffers and pan the display. But in any case,
>you probably will have to process buffers, but your most important
>advantage is, that you won't have to copy data, you only have to move
>pointers around.
The method that you describe is exactly what I had in mind.
It would be more correct to say it is "minimum" CPU intervention and not
without CPU intervention.
As far I understand, I can implement MMAP method for frame buffer device and
pass this pointer directly to mx3_camera driver with use USERPTR method, then
send queue and dequeue buffers to mx3_camera driver.
What is not clear, if it is possible to pass the same pointer of frame buffer
in mx3_camera, if the driver is using two buffers?
Thanks,
Alex Gershgorin
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