Is PFIFO an engine in nouveau kernel?

I recently received the following error in my syslog:

syslog:Apr 28 09:59:02 vostrodell kernel: [  883.401212] nouveau 0000:01:00.0: fb: trapped read at 0039824400 on channel 12 [3ed04000 systemd-logind[576]] engine 05 [PFIFO] client 08 [PFIFO_READ] subclient 01 [SEMAPHORE] reason 00000002 [PAGE_NOT_PRESENT]

So I went to the documentation:

• https://nouveau.freedesktop.org/KernelModuleParameters.html#debug

and I tried adding the following file:

$ cat /etc/modprobe.d/nouveau.conf # debug nouveauoptions nouveau debug="PFIFO=debug"

However this is not being passed as expected:

# cat /sys/module/nouveau/parameters/debug (null)

I understand that PFIFO is not listed under debug section on the documentation page, but should fall under the category of any engine (see above):

• https://nouveau.freedesktop.org/KernelModuleParameters.html#config

I believe this is the correct engine to pass as kernel module parameter.

Did I misread the documentation ? What should be the correct way to track to gather some meaning full information about this bug (in case I reproduce it) ?