etnaviv fails probe early, but succeeds after rmmod && modprobe

[Ing. Josua Mayer]

Greetings everybody,

While testing Debian on the i.MX6 HummingBoard, I came across a problem 
where after boot, the /dev/dri/card1 representing the GC2000 does not exist.

However at that point issuing
rmmod etnaviv; modprobe etnaviv
succeeds and I can then go on running applications uing GL.

So I am very unsure how to debug this. What I have so far is this output 
from dmesg [1], which points at some deferred probing timeout behaviour.
I do not know how to trace
(1) whose timeout exceeded
(2) what dependency is being ignored
(3) why after 3 attempts probing apparently gives up
I do know that this problem is shared with the coda driver, which fails 
the same way. Hence maybe this is not an etnaviv problem - but hopefully 
this message can still reach somebody who understands what is happening 
here.

Yours sincerely
Josua Mayer

[1] short dmesg (full dmesg attached):
root at sr-imx6:~# dmesg | grep etna
[    5.969888] etnaviv-gpu 130000.gpu: deferred probe timeout, ignoring 
dependency
[    5.985970] etnaviv-gpu: probe of 130000.gpu failed with error -110
[    6.076604] etnaviv-gpu 134000.gpu: deferred probe timeout, ignoring 
dependency
[    6.102833] etnaviv-gpu: probe of 134000.gpu failed with error -110
[    6.121231] etnaviv-gpu 2204000.gpu: deferred probe timeout, ignoring 
dependency
[    6.150314] etnaviv-gpu: probe of 2204000.gpu failed with error -110
root at sr-imx6:~# rmmod etnaviv
root at sr-imx6:~# modprobe etnaviv
root at sr-imx6:~# dmesg | grep etna
...
[  166.482349] etnaviv etnaviv: bound 130000.gpu (ops gpu_ops [etnaviv])
[  166.502064] etnaviv etnaviv: bound 134000.gpu (ops gpu_ops [etnaviv])
[  166.514261] etnaviv etnaviv: bound 2204000.gpu (ops gpu_ops [etnaviv])
[  166.520868] etnaviv-gpu 130000.gpu: model: GC2000, revision: 5108
[  166.527630] etnaviv-gpu 134000.gpu: model: GC320, revision: 5007
[  166.533879] etnaviv-gpu 2204000.gpu: model: GC355, revision: 1215
[  166.540048] etnaviv-gpu 2204000.gpu: Ignoring GPU with VG and FE2.0
[  166.547379] [drm] Initialized etnaviv 1.3.0 20151214 for etnaviv on 
minor 1
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