Webcam fails to output video stream

[xynnelt]

The webcam on my MacBook Air (M2), doesn't work. The hardware gets detected, but when trying to access the video stream it always fails (see logs for more info). In macOS the webcam works exactly as expected.

I have no clue as to what could be the issue. Hope someone here can shed some light on it. Please let me know if any additional information is needed!

OG post: Reddit

Setup:

Machine: MacBook Air (M2, 15-inch, 2023, 24GB RAM, 512GB)
Distro: Fedora Linux Asahi Remix 41 (but also had this problem on the 40 release, the camera has never worked under Asahi)
Kernel: 6.13.8-400.asahi.fc41.aarch64+16k

Relevant logs:

kernel.log : boot computer -> open chromium -> try to test using https://webcamtests.com/

[LittleBlueBreeze]

I am having an issue with my webcam as well, but with a MacBook Air M1. Everything works perfectly in Firefox, including microphone, but things get weird on my desktop. When I open the Camera app, everything is frozen and green. When I record sound using the Sound Recorder app, it only plays back out of the left side. I'm up to date on everything, using the Fedora Asahi remix.

[allmazz]

have similar problem on m2 max: camera doesn't work via GNOME Camera app, but does in Cheese app.

[LittleBlueBreeze]

Oh yeah, interesting! Can confirm my camera works fine in Cheese as well after downloading it.

[chadmed]

This is a known issue with the GNOME camera app and we cannot fix or work around it. GNOME Camera is likely picking the highest vertical resolution supported by our driver, which is line-padded to prevent the ISP from acting weird. This is perfectly fine in V4L2, and apps which cannot handle it gracefully are broken. Please raise this with GNOME if it hasn't been already.

[LittleBlueBreeze]

It looks like there is an open issue about this on GNOME's GitLab already: https://gitlab.gnome.org/GNOME/snapshot/-/issues/315

[rmader]

FTR., it turned out to be a Mesa issue: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38160

[mkurz]

FTR., it turned out to be a Mesa issue: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38160

and in turn a pipewire issue: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/4957

[rmader]

And a kernel bug 😅 https://gitlab.freedesktop.org/mesa/mesa/-/issues/14217#note_3173360

[jannau]

Kernel issue is resolved in https://github.com/AsahiLinux/linux/tree/asahi-wip - Hit another issue in the v4l2 dma-sg videobuffer mmap code, fixed downstream but not yet sent upstream.
Vulkan NV12 import is fixed in https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38200

Quite a collection of bugs

[jannau]

The asahi kernel issue is resolved in asahi-6.17.7-2 and later (available in Fedora-Asahi-Remix as 6.17.9-400.asahi).
The mesa issue is resolved in mesa-25.2.7 and mesa-25.3 (mesa-25.3 is not recommended due to https://gitlab.freedesktop.org/mesa/mesa/-/issues/14309).
The FreeDesktop flatpak runtime is still on mesa-25.2.6 so flatpak applications from flathub are still broken. The fedora flatpak runtimes have mesa-25.2.7.

GNOME Camera still only intermittently display a frame from the webcam (now looking as expected) due to a pipewire and/or gstreamer issue tracked in https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/4957

The minor fix from https://gitlab.freedesktop.org/pipewire/pipewire/-/merge_requests/2582 hasn't made it into Fedora 43 yet.

[jannau]

The cause for for the intermittent rendering of frames is identified and a fix for the main cause is submitted in https://gitlab.freedesktop.org/pipewire/pipewire/-/merge_requests/2636

[davidvfx07]

Just chiming in to add that I'm experiencing this too on my MacBook Air M2 that's fully updated afaik. No webcam app I've tried works (all of them being Flatpaks if that changes things). The ones I've tried are Kamuso, Cheese, Camera, and Webcamoid. In some I see a single underexposed frame as if the feed was being captured but was cut before the webcam could auto expose, and others don't work at all. However in the Zen Browser (basically FireFox) it works just fine.

[jannau]

that's expected. There is no pipewire release with the bug fixes. I hope there will be one in the next 2-3 weeks.