On 2011-08-30 08:20, Laurent Pinchart wrote:

Hi Gary,

On Tuesday 30 August 2011 16:18:00 Gary Thomas wrote:

quoted

On 2011-08-30 08:08, Gary Thomas wrote:

quoted

On 2011-08-29 04:49, Laurent Pinchart wrote:

quoted

On Thursday 25 August 2011 18:07:38 Gary Thomas wrote:

quoted

Background: I have working video capture drivers based on the
TI PSP codebase from 2.6.32. In particular, I managed to get
a driver for the TVP5150 (analogue BT656) working with that kernel.

Now I need to update to Linux 3.0, so I'm trying to get a driver
working with the rewritten ISP code. Sadly, I'm having a hard
time with this - probably just missing something basic.

I've tried to clone the TVP514x driver which says that it works
with the OMAP3 ISP code. I've updated it to use my decoder device,
but I can't even seem to get into that code from user land.

Here are the problems I've had so far:
* udev doesn't create any video devices although they have been
registered. I see a full set in /sys/class/video4linux
# ls /sys/class/video4linux/
v4l-subdev0 v4l-subdev3 v4l-subdev6 video1 video4
v4l-subdev1 v4l-subdev4 v4l-subdev7 video2 video5
v4l-subdev2 v4l-subdev5 video0 video3 video6

It looks like a udev issue. I don't think that's related to the kernel
drivers.

quoted

Indeed, if I create /dev/videoX by hand, I can get somewhere, but
I don't really understand how this is supposed to work. e.g.
# v4l2-dbg --info /dev/video3
Driver info:
Driver name : ispvideo
Card type : OMAP3 ISP CCP2 input
Bus info : media
Driver version: 1
Capabilities : 0x04000002
Video Output
Streaming

* If I try to grab video, the ISP layer gets a ton of warnings, but
I never see it call down into my driver, e.g. to check the current
format, etc. I have some of my own code from before which fails
miserably (not a big surprise given the hack level of those programs).
I tried something off-the-shelf which also fails pretty bad:
# ffmpeg -t 10 -f video4linux2 -s 720x480 -r 30 -i /dev/video2
junk.mp4

I've read through Documentation/video4linux/omap3isp.txt without
learning much about what might be wrong.

Can someone give me some ideas/guidance, please?

In a nutshell, you will first have to configure the OMAP3 ISP pipeline,
and then capture video.

Configuring the pipeline is done through the media controller API and
the V4L2 subdev pad-level API. To experiment with those you can use the
media-ctl command line application available at
http://git.ideasonboard.org/?p=media- ctl.git;a=summary. You can run it
with --print-dot and pipe the result to dot -Tps to get a postscript
graphical view of your device.

Here's a sample pipeline configuration to capture scaled-down YUV data
from a sensor:

./media-ctl -r -l '"mt9t001 3-005d":0->"OMAP3 ISP CCDC":0[1], "OMAP3 ISP
CCDC":2->"OMAP3 ISP preview":0[1], "OMAP3 ISP preview":1->"OMAP3 ISP
resizer":0[1], "OMAP3 ISP resizer":1->"OMAP3 ISP resizer output":0[1]'
./media-ctl -f '"mt9t001 3-005d":0[SGRBG10 1024x768], "OMAP3 ISP
CCDC":2[SGRBG10 1024x767], "OMAP3 ISP preview":1[YUYV 1006x759], "OMAP3
ISP resizer":1[YUYV 800x600]'

After configuring your pipeline you will be able to capture video using
the V4L2 API on the device node at the output of the pipeline.

Thanks for the info.

When I run 'media-ctl -p', I see the various nodes, etc, and they all
look good except that I get lots of messages like this:
- entity 5: OMAP3 ISP CCDC (3 pads, 9 links)
type V4L2 subdev subtype Unknown
pad0: Input v4l2_subdev_open: Failed to open subdev device node

Could this be related to my missing [udev] device nodes?

It could be. You need the /dev/video* and /dev/v4l-subdev* device nodes.

Yes, that helped a lot.  When I create the devices by hand, I can now see
my driver starting to be accessed (right now it's very much an empty stub)

Any ideas why udev (version 164) is not making these nodes automatically?

quoted

I can see media-ctl get confused and try to open a nonsense device name.
Here's what I see when I run
    # strace media-ctl -p | grep open
    open("/dev/media0", O_RDWR)             = 3
    open("", O_RDWR)                        = -1 ENOENT (No such file or
directory) write(1, "\tpad0: Input v4l2_subdev_open: F"..., 66) = 66

quoted

When I try to setup my pipeline using something similar to what you
provided, the first step runs and I can see that it does something (some
lines on the graph went from dotted to solid), but I still get errors:
# media-ctl -r -l '"tvp5150m1 2-005c":0->"OMAP3 ISP CCDC":0[1], "OMAP3
ISP CCDC":1->"OMAP3 ISP CCDC output":0[1]' Resetting all links to
inactive
Setting up link 16:0 ->  5:0 [1]
Setting up link 5:1 ->  6:0 [1]
# media-ctl -f '"tvp5150m1 2-005c":0[SGRBG12 320x240], "OMAP3 ISP
CCDC":0[SGRBG8 320x240], "OMAP3 ISP CCDC":1[SGRBG8 320x240]' Setting up
format SGRBG12 320x240 on pad tvp5150m1 2-005c/0
v4l2_subdev_open: Failed to open subdev device node
Unable to set format: No such file or directory (-2)

As far as I can tell, none if this is making any callbacks into my
driver.

Any ideas what I might be missing?

Thanks

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------