error: Datapath-v4l2 error on galicaster init

[andiempettJISC]

rarely, when galicaster starts up and there's NO video signal, the datapath v4l2 drivers fail to start correctly giving a green screen, try to record this an the pipeline fails with an error:

to replicate have a capture agent with datapath connected but with no video signal so you see the datapath timer. keep restarting galicaster. green screen should appear after 10+ trys

galicaster      2017-04-28 14:12:12,775 ERROR   recorder/service        Handle error (Driver error)
galicaster      2017-04-28 14:12:12,829 ERROR   recorder/service        Handle error (Driver error)
galicaster      2017-04-28 14:12:12,830 INFO    opencast/service        Init opencast client
galicaster      2017-04-28 14:12:12,839 INFO    opencast/service        Set status idle to server
galicaster      2017-04-28 14:12:12,840 INFO    opencast/client Sending state idle
galicaster      2017-04-28 14:12:12,842 ERROR   recorder/recorder       gst-resource-error-quark: Cannot 
identify device '/dev/video0'. (3) (v4l2_calls.c(606): gst_v4l2_open (): /GstPipeline:galicaster_recorder
/galicaster+recorder+bins+v4l2+GCv4l2:galicaster+recorder+bins+v4l2+gcv4l2-0/GstBin:bin0/GstV4l2Src:gc-v4
l2-src:
system error: No such file or directory)
galicaster      2017-04-28 14:12:12,842 ERROR   recorder/service        Handle error (gst-resource-error-
quark: Cannot identify device '/dev/video0'. (3) (v4l2_calls.c(606): gst_v4l2_open (): /GstPipeline:galic
aster_recorder/galicaster+recorder+bins+v4l2+GCv4l2:galicaster+recorder+bins+v4l2+gcv4l2-0/GstBin:bin0/Gs
tV4l2Src:gc-v4l2-src:
system error: No such file or directory))

attached is the syslog
datapath-v4l2-error.txt

reloading the profile gets rid of this error
attempted to install latest 16.04 and drivers with no success. reloading profile (restarting galicaster) helps

[smarquard]

It may be worth testing this with gstreamer 1.10.

[ppettit]

you can also try switching to the hwe kernel/xorg with sudo apt-get install linux-generic-hwe-16.04 xserver-xorg-hwe-16.04 which gives you a 4.8 kernel. i've not seen this issue (yet!) with that and datapath driver 7.14.0.254

[ppettit]

not sure if this is related, but i've been doing some more testing and occasionally (less than 1 in 10) on startup i get the following message in the log and a black rather than green screen (though maybe that is more to do with the graphics hardware/drivers?):

galicaster      2017-05-18 12:45:49,831 ERROR   recorder/recorder       Timeout getting recorder status, current status: (<enum GST_STATE_CHANGE_ASYNC of type Gst.StateChangeReturn>, state=<enum GST_STATE_PAUSED of type Gst.State>, pending=<enum GST_STATE_PLAYING of type Gst.State>)
galicaster      2017-05-18 12:45:49,831 ERROR   recorder/service        Handle error (Timeout getting recorder status, current status: (<enum GST_STATE_CHANGE_ASYNC of type Gst.StateChangeReturn>, state=<enum GST_STATE_PAUSED of type Gst.State>, pending=<enum GST_STATE_PLAYING of type Gst.State>))

dumping the gstreamer graph, everything looks the same as when it works except all the nodes are in the NULL state instead of PLAYING.

it is fixed by pressing the 'swap' button to reload the profile.

there is nothing (other than the usual junk from the datapath driver about unknown pixel formats) in the system logs.

[smarquard]

"Timeout getting recorder status" is fixed in #493 (at least we haven't seen it again since updating to a version that included that change).

[ppettit]

thanks @smarquard that seems to have fixed it here too. sorry for butting in here.

[andiempettJISC]

i can confirm gst 1.10+ and possibly newer kernels fix this (also fix random muted audio bug)