To summarize once more:

Actual behavior:
On the Lenovo ThinkPad T14s Gen 6 with Ubuntu 26.04 LTS and kernel 
7.0.0-15-generic, the Chicony integrated camera (04F2:B83F) exposes a HID 
sensor hub that creates two IIO devices: HID-SENSOR-200011.2.auto -> 
iio:device0 and HID-SENSOR-200011.4.auto -> iio:device1. Both devices appear to 
be proximity/attention sensors only (prox), and no ambient light / illuminance 
channel is exposed to userspace.

Expected behavior:
If this hardware includes a combined proximity + ambient light sensor, the 
kernel’s HID/IIO stack should expose the ALS portion as an IIO light device 
with attributes such as in_illuminance_raw and in_illuminance_scale, so that 
iio-sensor-proxy and desktop environments can use it for automatic screen 
brightness.

Impact:
Because no ALS-related sysfs attributes are present under 
/sys/bus/iio/devices/, iio-sensor-proxy cannot publish an ambient light sensor 
to userspace. As a result, GNOME/KDE auto-brightness does not work on this 
system.

Additional notes:
The issue appears to be a partial HID/IIO support problem for the Chicony 
04F2:B83F sensor hub, where the proximity part is detected but the ALS part is 
not mapped to userspace.

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2151784

Title:
  No ALS (ambient light sensor) exposed on ThinkPad T14s Gen 6 – Chicony
  04F2:B83F HID sensor hub only provides proximity IIO devices

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2151784/+subscriptions


-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to