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] 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 nouveau options 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) ?