how can deal with the stream in only on-the-fly-output available HW block??

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-----Original Message-----
From: Kim, HeungJun [mailto:riverful.kim@xxxxxxxxxxx]
Sent: Tuesday, September 14, 2010 2:02 PM
To: 'laurent.pinchart@xxxxxxxxxxxxxxxx'; 'hverkuil@xxxxxxxxx'
Subject: RE: how can deal with the stream in only on-the-fly-output
available HW block??

> On Monday, September 13, 2010 14:10:55 Kim, HeungJun wrote:
> > Hi all,
> >
> >
> >
> > What if some SoC's specific HW block supports only on-the-fly mode for
> > stream output??
>
> What do you mean with 'on-the-fly mode'? Does that mean that two HW
blocks
> are linked together so that the video stream goes directly from one to
the
> other without ever being DMA-ed to memory?

You're right. It's linked with internal SRAM FIFO. So, syncing streams
with both blocks is kept with VSync Interrupt. It's not using DMA-ed to
memory in this mode.

>
> >
> > In this case, what is the suitable buf_type??
>
> Suitable buf_type for doing what?

I wanna define this blocks topology with V4L2 APIs. But, I don't find
suitable buf_type or any definitions in the V4L2 APIs with current SoC's
block media topology.

>
> You probably need the upcoming media API to be able to correctly deal
with
> these issues. Check the mailing list for the patches done by Laurent
> Pinchart.
>
> The current V4L2 API is really not able to handle changes in the
internal
> video stream topology.

Thanks to Hans. It's very helpful.
I'll check Laurent's media topology patches.


Hello, Laurent,

I'm googling and find your patches, so I'm checking with. But, where can I
get your patches?? Probably, I would find in this page :
http://git.linuxtv.org/, so what's your repository?

Regards,
HeungJun, Kim

>
> Regards,
>
> 	Hans
>
> >
> > I'm faced with such problem.
> >
> >
> >
> > As explanation for my situation briefly, the processor I deal with now
> has 3
> > Multimedia H/W blocks, and the problem-one in the 3 blocks do the work
> for
> > sensor-interfacing and pre-processing.
> >
> > It supports CCD or CMOS for input, and DMA or On-The-Fly for output.
> > Exactly, it has two cases - DMA mode using memory bus & On-The-Fly
 mode
> > connected with any other multimedia blocks.
> >
> > Also, it use only one format "Bayer RGB" in case of mode the DMA and
> > On-The-Fly mode both.
> >
> >
> >
> > So, when the device operates in the On-The-Fly mode, is it alright the
> > driver's current type is  V4L2_BUF_TYPE_VIDEO_CAPTURE? or something
else?
> >
> > or if setting buf_type is wrong itself, what v4l2 API flow is right
for
> > driver or userspace??
> >
> >
> >
> > the v4l2 buf_type enumeratinos is defined here, but I have no idea
about
> > suitable enum value in this case, also except for any other under
enums
> too.
> >
> >
> >
> > V4L2_BUF_TYPE_VIDEO_CAPTURE        = 1,
> >
> > V4L2_BUF_TYPE_VIDEO_OUTPUT         = 2,
> >
> > V4L2_BUF_TYPE_VIDEO_OVERLAY        = 3,
> >
> > V4L2_BUF_TYPE_VBI_CAPTURE          = 4,
> >
> > V4L2_BUF_TYPE_VBI_OUTPUT           = 5,
> >
> > V4L2_BUF_TYPE_SLICED_VBI_CAPTURE   = 6,
> >
> > V4L2_BUF_TYPE_SLICED_VBI_OUTPUT    = 7,
> >
> > V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY = 8,
> >
> > V4L2_BUF_TYPE_PRIVATE              = 0x80,
> >
> >
> >
> > I'll thanks for any idea or answer.
> >
> >
> >
> > Regards,
> >
> > HeungJun, Kim
> >
> >
> >
> >
>
> --
> Hans Verkuil - video4linux developer - sponsored by TANDBERG, part of
> Cisco

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