Comment # 25 on bug 1225352 from Andrea della Porta

I confirm that build 13.224 does not work (hangs as expected by the ticket),
just like 13.217: in fact they share the exact same kernel.
Some further info: adding modprobe.blacklist=vc4 avoid the issue and let the
Rpi3 boot correctly (albeit without monitor support). On rpi4, everything is ok
and vc4 module does not hang.

Also, on rpi3, this is the ftrace stack when it hangs (on vc4 module only:
"echo '*:mod:vc4' > set_ftrace_filter"):

2)              | vc4_drm_register [vc4]() {
 2) + 12.813 us  |   vc4_hvs_dev_probe [vc4]();
 2) + 30.521 us  |   vc4_hdmi_dev_probe [vc4]();
 2) + 54.844 us  |   vc4_vec_dev_probe [vc4]();
 2) + 21.146 us  |   vc4_txp_probe [vc4]();
 2) + 18.855 us  |   vc4_crtc_dev_probe [vc4]();
 2)  7.656 us   |   vc4_crtc_dev_prob

there's report in this ticket that 15.6 works (I've not tried it by myself
yet), and from 15.5 (kernel 5.14) to 15.6 (kernel 6.4) there's plenty of kernel
commits related to vc4, two of which (at least) may be worth our attention
since solve crashes: 797d72ce8e0f8 and c86b41214362e8e.

Reassigning to the HW enablement team. 
Many thanks,
Andrea