No signal on composite (aka cvbs) output

[Osiander]

Hello guys,

so, today I've make a adapter cable for video output, like described in this thread (tip = shield and first ring is video signal) and conntected them to my Rock64 and my DELL 2007FP.

After power on........ nothing. So picture on the monitor....

Do I have to setup something else?


I'm using Debian Stretch 0.6.44. If I connect the board per HDMI, I get the signal.

All logs (u-boot, printenv and boot) are attached.

Many thanks.

[Osiander]

After googling aroung, I've checked the /sys/class/drm directory. So here is just HDMI-1:

root@rock64:~# cd /sys/class/drm/
root@rock64:/sys/class/drm# ll
total 0
drwxr-xr-x  2 root root    0 Jul 15 17:51 .
drwxr-xr-x 64 root root    0 Jul 15 17:51 ..
lrwxrwxrwx  1 root root    0 Jul 15 17:51 card0 -> ../../devices/platform/display-subsystem/drm/card0
lrwxrwxrwx  1 root root    0 Jul 15 17:51 card0-HDMI-A-1 -> ../../devices/platform/display-subsystem/drm/card0/card0-HDMI-A-1
lrwxrwxrwx  1 root root    0 Jul 15 17:51 controlD64 -> ../../devices/platform/display-subsystem/drm/controlD64
lrwxrwxrwx  1 root root    0 Jul 15 17:51 renderD128 -> ../../devices/platform/display-subsystem/drm/renderD128
-r--r--r--  1 root root 4096 Jul 15 17:51 version
root@rock64:/sys/class/drm#

So, I think here is my problem, here should be "card0-Composite-1" or something like that... It looks like Rock64 didn't recognize CVBS output...

Any ideas?

[tllim]

After googling aroung, I've checked the /sys/class/drm directory. So here is just HDMI-1:

root@rock64:~# cd /sys/class/drm/
root@rock64:/sys/class/drm# ll
total 0
drwxr-xr-x  2 root root    0 Jul 15 17:51 .
drwxr-xr-x 64 root root    0 Jul 15 17:51 ..
lrwxrwxrwx  1 root root    0 Jul 15 17:51 card0 -> ../../devices/platform/display-subsystem/drm/card0
lrwxrwxrwx  1 root root    0 Jul 15 17:51 card0-HDMI-A-1 -> ../../devices/platform/display-subsystem/drm/card0/card0-HDMI-A-1
lrwxrwxrwx  1 root root    0 Jul 15 17:51 controlD64 -> ../../devices/platform/display-subsystem/drm/controlD64
lrwxrwxrwx  1 root root    0 Jul 15 17:51 renderD128 -> ../../devices/platform/display-subsystem/drm/renderD128
-r--r--r--  1 root root 4096 Jul 15 17:51 version
root@rock64:/sys/class/drm#

So, I think here is my problem, here should be "card0-Composite-1" or something like that... It looks like Rock64 didn't recognize CVBS output...

Any ideas?

If both HDMI and CVBS plug in at the same time, I thinks the video route to HDMI output. Just unplug the HDMI cable form ROCK64 board and keep the AV cable plugin,  there may be CVBS output.

[Osiander]

No, the problem is different, under /sys/class/drm there is no device for composite output (should be called composite, TV or something similar). I didn't do that.

But, in the meantime, I'm a bit further along. After I modified the DTS file (added an &tve), there is now also a device for composite output:

Code:

root@rock64:~# tree /sys/class/drm/
/sys/class/drm/
|-- card0 -> ../../devices/platform/display-subsystem/drm/card0
|-- card0-HDMI-A-1 -> ../../devices/platform/display-subsystem/drm/card0/card0-HDMI-A-1
|-- card0-TV-1 -> ../../devices/platform/display-subsystem/drm/card0/card0-TV-1
|-- controlD64 -> ../../devices/platform/display-subsystem/drm/controlD64
|-- renderD128 -> ../../devices/platform/display-subsystem/drm/renderD128
-- version

The status of the device is connected:

And I also have that the modes are correct, Rock64 supports for composite only these two:

Code:

root@rock64:# cat /sys/class/drm/card0-TV-1/modes
720x576i50
720x480i60

And I also see that the correct mode is selected (720x576i50):

Code:

root@rock64:# cat /sys/class/drm/card0-TV-1/mode
720x576i50
root@rock64:#

But, I still can't get a picture on the TV. Only the composite cable is connected, no HDMI.

I attached the DTS file and dmesg output.