Not sure if this is the correct forum, but I believe I have some issue with nvidia graphics driver installation from graphics-drivers Ubuntu PPA. Sometimes (after nvidia driver version upgrade, 367.18 beta for now) module options[NVreg_EnablePCIeGen3] defined in /etc/modprobe.d separate file start to be ignored at boot, even if I update module name(alias) to nvidia_367. (this has also happened before for some older versions). If I do the modprobe nvidia manually after boot(previously switching to VT console and rmmod all nvidia modules), it works: nvidia-settings and nvidia-smi report PCIe gen3 is enabled, I see modprobe -v adds module parameter on insert, but systool -vm nvidia still shows no module parameters(maybe another module glitch?). Adding parameter nvidia.NVreg_EnablePCIeGen3=1 to kernel cmdline before boot seems to also not work...Has anyone experienced smth like this, maybe for other [external] kernel modules? Is there some stable solution for this?

Answer was quite simple, for any kernel module(not only nvidia), in ubuntu I have to manually run

every time after any changes to kernel modules(including /etc/modprobe.d files). After any kernel or module update by apt this is done automatically, so any changes to files in /etc/modprobe.d are also applied: that's why sometimes it seemed to work without any manual steps. So the only left bug in nvidia module is not updating sysfs to show applied parameters values.