Hi Gary, 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. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
