What's needed for an OpenCL accelerated darktable in Manjaro?

mikae1 · December 21, 2021, 8:07pm

Hi! My GTX 970M mostly gives me the option to “activate OpenCL support” in darktable.

However, after a few days (or hours) of uptime it becomes grayed out and I must reboot Manjaro KDE to get the option back. It’s the same with NVENC in OBS.

I don’t start OBS or darktable with prime-run, but I’ve tried to and it doesn’t seem to make any difference. Once the OpenCL option is gone I have to reboot.

I wonder if I have all the packages needed for stable OpenCL acceleration in darktable. I’m using the proprietary Nvidia drivers and I have have the following packages when searching for “nvidia” in pamac:

nvidia-prime
nvidia-utils
lib32-nvidia-utils
linux510-nvidia
mhwd-nvidia
mhwd-nvidia-390xx
mhwd-nvidia-470xx
opencl-nvidia

I saw somewhere that the (4 GB!) cuda package was also recommended. I don’t have optimus-manager. Are any of these recommended or necessary? Am I missing anything else?

Claes · December 21, 2021, 8:21pm

Why on earth would it grey out? Sounds as if something is not really stable.

It is a long time since I was using Manjaro, I’ll see if I can dig up some notes from that time. One thing needed in those days, I recall, was ocl-icd.

– a little later –

Found it:

Have fun!
Claes in Lund, Sweden

kofa · December 21, 2021, 9:16pm

There have been a few OpenCL-related topics. Your card or your machine could be running out of memory. You could increase the opencl memory headroom parameter.

I’m on a tram now, but search for opencl in recent topics (the past two months).

Edit: found this

betazoid · December 21, 2021, 10:01pm

If your computer goes to suspend/standby/sleep while darktable is active, opencl will be disable and you need to reboot. I think it’s and Nvidia “bug”. I think there is some experimental script or so to prevent this for Fedora.
The only way to prevent this is closing darktable if you know that your PC will suspend.

mikae1 · December 21, 2021, 10:24pm

Thank you @betazoid! I was able to reproduce the error with you information. Once I close the lid while darktable is running it’s goodbye to OpenCL and only a restart works. Arghh… This is extremely frustrating. I mean, it’s a laptop.

kofa · December 21, 2021, 10:27pm

If that is the case, unloading and reloading (some of the) nvidia modules might work. I’ve already turned my computer off for the night. Try lsmod, rmmod and modprobe.

mikae1 · December 21, 2021, 10:51pm

Thanks! I’ll try to explore that. If you come up with something when you’re at the computer, I’m all ears.

mikae1 · December 21, 2021, 10:58pm

Don’t know if this could work on Manjaro:

sudo rmmod nvidia_uvm
sudo modprobe nvidia_uvm

I’ll give it a try tomorrow.

EDIT: This is giving me high hopes. Not elegant, but better than reboot.

facing same issue on manjaro linux. the temporary fix mentioned here works.

elstoc · December 21, 2021, 11:06pm

The cuda package isn’t required for darktable. I would advise reading the Arch Linux Wiki and linked topics if you haven’t already.

mikae1 · December 22, 2021, 9:24am

sudo rmmod nvidia_uvm
sudo modprobe nvidia_uvm

Did the trick. OpenCL is available in darktable again after disappearing due to closing the lid.

I guess I just need to automate this when opening the lid and getting the machine out of sleep.

Brian_Innes · December 22, 2021, 11:48am

Or close darktable before putting the machine to sleep?

mikae1 · December 22, 2021, 5:20pm

You have too high thoughts about my ability to remember simple things.
But yeah, darktable has to be restarted anyway. Or else it won’t find OpenCL again after doing:

It’s a very welcome alternative to rebooting the computer for those times you forget to exit every OpenCL accelerated application before closing the lid.