mir-on-x11 with nested server causes lockup and kernel complaint

[Kevin DuBois]

DISPLAY=:0.0 bin/mir_demo_server --file /tmp/a
and
bin/mir_demo_server --file /tmp/b --host-socket /tmp/a
and
bin/mir_demo_client_egltriangle

cause a lockup, and this complaint from the kernel (nouveau):
x11 window has corruption (orange/black/purple), and eventually the kernel recovers from this and things unlock.

[75159.696723] nouveau 0000:01:00.0: DRM: resuming kernel object tree...
[75159.829319] nouveau 0000:01:00.0: priv: HUB0: 10ecc0 ffffffff (1940822c)
[75159.849752] nouveau 0000:01:00.0: DRM: resuming client object trees...
[75165.628376] nouveau 0000:01:00.0: DRM: evicting buffers...
[75165.642723] nouveau 0000:01:00.0: DRM: waiting for kernel channels to go idle...
[75165.642746] nouveau 0000:01:00.0: DRM: suspending client object trees...
[75165.645653] nouveau 0000:01:00.0: DRM: suspending kernel object tree...
[75167.444494] nouveau 0000:01:00.0: DRM: resuming kernel object tree...
[75167.605614] nouveau 0000:01:00.0: priv: HUB0: 10ecc0 ffffffff (1940822c)
[75167.626205] nouveau 0000:01:00.0: DRM: resuming client object trees...
[75172.121577] nouveau 0000:01:00.0: DRM: Moving pinned object ffffa0b8e5e58c00!
[75172.124970] nouveau 0000:01:00.0: fifo: write fault at 0003a00000 engine 00 [GR] client 0f [GPC0/PROP_0] reason 02 [PTE] on channel 3 [007f918000 mir_demo_server[7161]]
[75172.124976] nouveau 0000:01:00.0: fifo: gr engine fault on channel 3, recovering...
[75172.138264] nouveau 0000:01:00.0: DRM: Moving pinned object ffffa0b8e5e58400!
[75172.154808] nouveau 0000:01:00.0: DRM: Moving pinned object ffffa0b8e5e5f800!
[75172.171397] nouveau 0000:01:00.0: DRM: Moving pinned object ffffa0b8e5e59c00!
[75182.683809] asynchronous wait on fence nouveau:mir_demo_server[7161]:18091 timed out
[75182.683814] asynchronous wait on fence nouveau:mir_demo_server[7161]:18090 timed out

[Cemil Azizoglu (cemil-azizoglu)]

Probably due to lack of multiple GPU support.

[Kevin DuBois (kdub)]

yep, it is, will mark dup of other one