On 2011-08-31 09:15, Laurent Pinchart wrote:
Hi Gary,
On Wednesday 31 August 2011 14:01:07 Gary Thomas wrote:
On 2011-08-31 05:00, Laurent Pinchart wrote:
On Wednesday 31 August 2011 12:56:29 Gary Thomas wrote:
On 2011-08-31 02:13, Laurent Pinchart wrote:
On Wednesday 31 August 2011 02:07:36 Gary Thomas wrote:
On 2011-08-30 16:50, Laurent Pinchart wrote:
On Wednesday 31 August 2011 00:45:39 Gary Thomas wrote:
On 2011-08-29 04:49, Laurent Pinchart wrote:
On Thursday 25 August 2011 18:07:38 Gary Thomas wrote:
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.
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.
Getting somewhere now, thanks. When I use this full pipeline, I can
get all the way into my driver where it's trying to start the data.
What if I want to use less of the pipeline? For example, I'd
normally be happy with just the CCDC output. How would I do that?
Then connect CCDC's pad 1 to the CCDC output video node and capture
on that video node.
What pixel format would I use with ffmpeg?
What does your subdev deliver ?
It's a BT656 encoder - 8-bit UYVY 4:2:2
Then you will first have to add YUV support to the CCDC. It wouldn't be
fun if it worked out of the box, would it ? :-)
So, functionality that was present in 2.6.32 (TI PSP version at least)
is not currently available?
That's right. You can blame TI for not pushing it to mainline :-)
Is this only important if I want to push data past the CCDC? In the past,
we were happy with just using the CCDC like a frame grabber which
delivered YUV data to memory [raw data from /dev/videoN] Is this possible
with the CCDC support as is? The only discussion I could find about this
on this list was in early March 2011 and I think you implied that it
should work. I'm a bit concerned that it won't as the BT656 data has
embedded syncs that the CCDC needs to be set up for.
The CCDC needs to be setup for BT.656 synchronization. That shouldn't be
difficult.
I saw a reference to 'Add YUV support to CCDC' on 2010-11-15, but no
followup. That work seemed to be for a much older driver and not
applicable to the current work, or am I missing something?
Sergio Aguirre worked on YUV support in the CCDC some time ago. The patch
didn't make it as-is as some changes were needed, and it hasn't been reworked
since.
Has there been other discussion on this topic (I didn't see it in onthis
list which I've been quietly monitoring for two years)? Is the lack of
YUV support in CCDC for this current driver (drivers/media/video/omap3isp)
a concious decision, or just a lack of movement?
Just a lack of movement. It should not be difficult to implement.
Is there someone at TI that I should contact?
TI moved to the OMAP4, I'm not sure if there's anyone still working on the
OMAP3 ISP there.
Ah the peril of being marketing (not necessarily market) driven.
I'm just trying to understand what I have to do to move forward on this. I
really hadn't planned/scheduled a large effort to recreate functionality
that we've already been using for years when we moved to a newer kernel.
I've just sent three preliminary patches to the list to add YUYV support in
the OMAP3 ISP CCDC.
Thanks! I'll see if I can work through this (remember my sensor is also
early-days!).
That said though I can see that this new driver structure (with the
flexible elements and connections, etc) is a vast improvement on the old,
hard-wired stuff. I only hope I can figure out how to make it work with
my sensor.
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
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