Granular Power Savings Patches Posted For Common "uvcvideo" Linux Webcam Driver

[phoronix]

Phoronix: Granular Power Savings Patches Posted For Common "uvcvideo" Linux Webcam Driver

Google engineer Ricardo Ribalda has proposed a set of patches for the common "uvcvideo" kernel driver that supports UVC-compliant web cameras and the like to provide granular power saving support...

https://www.phoronix.com/news/uvcvideo-Granular-Power

[treba]

Very happy to see this. Right now projects like libcamera need to work around this by closing the FD of the device when not needed - something that was only introduced recently in order to avoid higher power usage on systems with libcamera and Pipewire, see e.g. https://gitlab.freedesktop.org/pipew.../-/issues/2669

[Mathias]

Very happy to see this. Right now projects like libcamera need to work around this by closing the FD of the device when not needed - something that was only introduced recently in order to avoid higher power usage on systems with libcamera and Pipewire, see e.g. https://gitlab.freedesktop.org/pipew.../-/issues/2669

I always wondered. ... powertop shows my camera using about half my power budget on my laptop - constantly. But when I shut down pipewire or onload the uvc module, the camera doesn't show up anymore, but the total power consumption is not reduced at all.

Hmm Fedora ships libcamera-0.3.2 I have to check tomorrow if it changed something... It would be awesome if it changed the power consumption.

[intelfx]

I always wondered. ... powertop shows my camera using about half my power budget on my laptop - constantly

You should ignore that column. It is a purely mathematic estimate, and the estimator algorithm in powertop is VERY bad.

[Mathias]

You should ignore that column. It is a purely mathematic estimate, and the estimator algorithm in powertop is VERY bad.

Yeah. I thought the same. Then I read a PSA that claimed the same thing and had workarounds and people claiming that it really helped double their battery life. But it didn't help me. Still, it has do waste something to be registered for that much...

[Adarion]

Sounds like a good invention, I just hope this will work without too much fallout (-> needing lots of quirks for whatever models of cameras).