[Letux-kernel] GTA04 camera driver

[H. Nikolaus Schaller]

Hi,
I think I am a little closer to finding the issue(s)...

First of all I observed that although power is properly
turned on (ov965x_s_power), there is no call to
ov965x_s_stream which IMO should turn on the video
stream. There is only a single call to ov965x_get_fmt()
as the only other activity after ov965x_s_power()
and before I stop mplayer (which calls ov965x_s_power()
to turn the camera module off). In log lines:

[  620.049804] ov965x_s_power: on: on
[  620.352020] ov965x_get_fmt(which=1)
[  628.761810] ov965x_s_power: on: off

Therefore, I have looked into the isp code where the
camera should be turned on. It looks like this is
done in isp_video_streamon().

Now some prinkt in isp_video_streamon() show that it
returns -EPIPE. Which appears as if it is not reported
to userspace and makes mplayer show a green screen.


[  620.049804] ov965x_s_power: on: on
[  620.147277] ov965x_write: 0x01 @ 0x09 (2)
[  620.151916] ov965x_write: 0x40 @ 0x15 (2)
[  620.157989] ov965x_write: 0x00 @ 0x11 (2)
[  620.162658] ov965x_write: 0x4a @ 0x6B (2)
[  620.178619] ov965x_write: 0x40 @ 0x0F (2)
[  620.183166] ov965x_write: 0x05 @ 0x3B (2)
[  620.200469] ov965x_write: 0xc0 @ 0x40 (2)
[  620.216857] ov965x_write: 0x50 @ 0x31 (2)
[  620.222351] ov965x_write: 0x88 @ 0x3A (2)
[  620.261779] isp_video_mmap()
[  620.268737] isp_video_mmap()
[  620.348297] isp_video_streamon()
[  620.352020] ov965x_get_fmt(which=1)
[  620.358184] isp_video_streamon() err -32

^^^^
vvvv ctrl-C to kill mplayer after some seconds

[  628.746398] isp_video_release()
[  628.749755] isp_video_streamoff()
[  628.761810] ov965x_s_power: on: off


This is now a very specific symptom ready for further
study...

Please keep fingers crossed that we can use this info
to find out why the module isn't showing a video...

BR,
Nikolaus