[Nouveau] [REGRESSION] nouveau: 30 second boot hang after commit 2b700825e

[Eric Biggers]

Hi Alexandre and Ben,

Any thoughts about what is causing this problem?  This bug is 100% reproducible
on my hardware with the stock Fedora 23 kernel as well as with Linux 4.5-rc7
when compiled with CONFIG_DEBUG_SHIRQ.  Note that with CONFIG_DEBUG_SHIRQ there
is an extra call to the IRQ handler made during free_irq(), and I suspect that
is enabling the problem somehow.

Eric