| 26 Jan 2026 |
 connor (burnt/out) (UTC-8) | Set it up to merge, apologies for how long that took. Thank you for the fix, Ari :) | 23:26:40 |
 Gaétan Lepage | Thanks for the reviews connor (burnt/out) (UTC-8).
Btw, if you have a minute for the cuda-bindings PR, that would help me unblocking torch.
https://github.com/NixOS/nixpkgs/pull/482638 | 23:36:41 |
| connor (burnt/out) (UTC-8) | Just reviewed, looks good. You might need to update the PR description to change python3Packages.cuda-bindings: init at 13.1.1 though | 23:40:28 |
| Gaétan Lepage | Thanks! | 23:46:49 |
| 29 Jan 2026 |
|  @oh_yeah:matrix.org left the room. | 00:14:51 |
| Gaétan Lepage | Hello everyone!
I want to share some news regarding the progress yorik.sar and I made on the infra. Some were already communicated, but it doesn't work to summarize everything.
- We have been building and caching all
cudaSupport-sensitive nixpkgs packages on both stable and unstable nixpkgs channels on our Hydra instance for a few weeks. You can check the cuda-packages-unstable and cuda-packages-stable jobsets.
- All
gpuCheck instances across nixpkgs are now automatically and exhaustively collected and built in Hydra as well. See the cuda-gpu-checks-unstable and cuda-gpu-checks-stable jobsets. For a reminder, gpuChecks are derivations that run some package tests that need access to a physical GPU.
- Regarding package maintenance and updates, recent times were hectic as nixpkgs received several breaking changes since the beginning of 2026 (recursing into
python314Packages, update to GCC 15 and more staging-next treats). Besides, here are notable ones:
- This is still an idea, but my plan is to create two cuda-specific nix channels:
nixos-unstable-cuda and nixos-stable-cuda where we could ensure that a curated set of package builds and tests are succesful (release blockers). I would be glad to hearing your feedback on this idea.
We're trying our best to move things forward as fast as possible. Unfortunately, time and compute resources are limited, so it's never fast enough 😅
Have a nice day! | 09:26:20 |
| Gaétan Lepage | * Hello everyone!
I want to share some news regarding the progress yorik.sar, connor (burnt/out) (UTC-8), SomeoneSerge (back on matrix) and I made recently. Some were already communicated, but it doesn't work to summarize everything.
- We have been building and caching all
cudaSupport-sensitive nixpkgs packages on both stable and unstable nixpkgs channels on our Hydra instance for a few weeks. You can check the cuda-packages-unstable and cuda-packages-stable jobsets.
- All
gpuCheck instances across nixpkgs are now automatically and exhaustively collected and built in Hydra as well. See the cuda-gpu-checks-unstable and cuda-gpu-checks-stable jobsets. For a reminder, gpuChecks are derivations that run some package tests that need access to a physical GPU.
- Regarding package maintenance and updates, recent times were hectic as nixpkgs received several breaking changes since the beginning of 2026 (recursing into
python314Packages, update to GCC 15 and more staging-next treats). Besides, here are notable ones:
- This is still an idea, but my plan is to create two cuda-specific nix channels:
nixos-unstable-cuda and nixos-stable-cuda where we could ensure that a curated set of package builds and tests are succesful (release blockers). I would be glad to hearing your feedback on this idea.
We're trying our best to move things forward as fast as possible. Unfortunately, time and compute resources are limited, so it's never fast enough 😅
Have a nice day! | 09:26:59 |
| Gaétan Lepage | * Hello everyone!
I want to share some news regarding the progress yorik.sar, connor (burnt/out) (UTC-8), SomeoneSerge (back on matrix) and I made recently. Some were already communicated, but it doesn't work to summarize everything.
- We have been building and caching all
cudaSupport-sensitive nixpkgs packages on both stable and unstable nixpkgs channels on our Hydra instance for a few weeks. You can check the cuda-packages-unstable and cuda-packages-stable jobsets.
- All
gpuCheck instances across nixpkgs are now automatically and exhaustively collected and built in Hydra as well. See the cuda-gpu-checks-unstable and cuda-gpu-checks-stable jobsets. For a reminder, gpuChecks are derivations that run some package tests that need access to a physical GPU.
- Regarding package maintenance and updates, recent times were hectic as nixpkgs received several breaking changes since the beginning of 2026 (recursing into
python314Packages, update to GCC 15 and more staging-next treats). Besides, here are notable ones:
- This is still an idea, but my plan is to create two cuda-specific nix channels:
nixos-unstable-cuda and nixos-25.11-cuda where we could ensure that a curated set of package builds and tests are succesful (release blockers). I would be glad to hearing your feedback on this idea.
We're trying our best to move things forward as fast as possible. Unfortunately, time and compute resources are limited, so it's never fast enough 😅
Have a nice day! | 09:27:55 |
 hexa (UTC+1) | nixos-25.11 should be fairly cheap on rebuilds | 14:12:03 |
| hexa (UTC+1) | the opencv 4.13.0 blocks openvino updates | 14:12:22 |
| hexa (UTC+1) | * the opencv 4.13.0 update blocks openvino updates | 14:12:27 |
| hexa (UTC+1) | * the opencv 4.13.0 update is required to update openvino too | 14:12:44 |
|  Gilles Poncelet joined the room. | 22:07:17 |
| 30 Jan 2026 |
| connor (burnt/out) (UTC-8) | Can someone review/merge https://github.com/NixOS/nixpkgs/pull/485211? | 02:20:04 |
| connor (burnt/out) (UTC-8) | Also coming up: https://github.com/NixOS/nixpkgs/pull/485208 | 03:10:33 |
|  matthewcroughan @fosdem changed their display name from matthewcroughan to matthewcroughan @fosdem. | 13:50:24 |
| 31 Jan 2026 |
 Bryan Honof | Hey hey, live from FOSDEM here. Is there an easy way to generate those manifest JSON files? Or is that a fully manual process? | 16:26:02 |
| Bryan Honof | Nevermind, should've read the READEME. :) | 16:26:59 |
| connor (burnt/out) (UTC-8) | Oh god is it up to date | 16:32:45 |
| connor (burnt/out) (UTC-8) | Those manifests should come directly from NVIDIA (but they need a new line added to comply with the Nixpkgs formatter) | 16:33:13 |
| 1 Feb 2026 |
|  Fernando Rodrigues changed their display name from SigmaSquadron to Fernando Rodrigues. | 10:43:22 |
| Gaétan Lepage | OpenCV 4.13.0 bump has just been merged! | 22:56:18 |
| 3 Feb 2026 |
 Kevin Mittman (UTC-8) | Hi Bryan Honof I can help answer questions about the JSON manifestsconnor (burnt/out) (UTC-8) You could have mentioned that, happy to add a newline at the end | 21:41:47 |
| connor (burnt/out) (UTC-8) | Gaétan Lepage: PR for fixes related to CUDA 13 breakages: https://github.com/NixOS/nixpkgs/pull/485208 | 22:06:42 |
| 4 Feb 2026 |
|  Yorusaka Miyabi joined the room. | 01:48:31 |
|  Benjamin Isbarn joined the room. | 09:10:02 |
| Benjamin Isbarn | Hi, I'm trying to run an application that uses OpenCV with cuda support built with nix on a NVIDIA® Jetson™ Orin™ Nano 8GB. This fails essentially with the following message:
Internal Error: OpenCV(4.11.0) /build/source/modules/dnn/src/cuda4dnn/init.hpp:55: error: (-217:Gpu API call) CUDA driver version is insufficient for CUDA runtime version in function 'getDevice'\n (code: GpuApiCallError, -217)
I did the old /run/opengl-driver/lib trick which worked flawlessly on another device which was a PC running a 3050. But this doesn't seem to work on the Jetson (I do see that the libcuda i symlinked in /run/opengl-driver/lib get's loaded when running it within strace). I tried to use the same cuda version thats on the Jetson (i.e.g cat /usr/local/cuda/version.json gave me "version" : "11.4.19" so I went with cuda_11_4 in nix.
Any help would highly be appreciated :) | 11:39:09 |
| connor (burnt/out) (UTC-8) | So your Orin is running JetPack 5, correct?
Where did you find/get cuda_11_4? I'm not aware of that. How did you build OpenCV, from which commit, how did you configure Nixpkgs, etc. | 20:13:16 |
| Gaétan Lepage | RE: effort to migrate towards cuda 13 treewide
magma fails to build with cuda 13. I opened https://github.com/NixOS/nixpkgs/pull/487064 to fix it.
| 22:37:31 |
| 5 Feb 2026 |
| connor (burnt/out) (UTC-8) | Merging; also made a backport for it since it's worth having there as well | 01:31:25 |
