[Bug 1926280] [NEW] ALS function lost after suspend/resume

Launchpad Bug Tracker 1926280 at bugs.launchpad.net
Tue Apr 27 10:43:35 UTC 2021

You have been subscribed to a public bug by Kai-Chuan Hsieh (kchsieh):


 * Some Dell machine support ALS (ambient light sensor) will lost function after suspend/resume
   It originally only report iio-buffer-als by udev rule, but the buffer no longer update after
   suspend/resume, the issue can be eliminated by polling in_illuminance_raw node.

[Test Plan]

 * Boot a machine with ALS support, and check it by
   $ cat /sys/bus/iio/devices/iio:device*/name => see if it contains name als
 * do suspend/stress by
   $ sudo -s
   # for i in `seq 20`; do sleep 5; rtcwake -m mem -s 10; done
 * run monitor-sensor and cover your hand on the light sensor
   $ monitor-sensor
 * if the als function lost, there should be no update of the ambient light sensor anymore

[Where problems could occur]

 * The change add in_illuminance_raw check and add iio-poll-als to
IIO_SENSOR_PROXY_TYPE for sensor using raw value.

 * It will keep original IIO_SENSOR_PROXY_TYPE and multiple
IIO_SENSOR_PROXY_TYPE support, so risk is low for other hardware.

 * Checking on working hardware and run $ monitor-sensor
   it should keep popping Light changed event no matter what operations,
   close lid, suspend/resume, reboot...etc.

[Other Info]

 * The change is from upstream which has been in groovy and hirsute.

** Affects: oem-priority
     Importance: Undecided
     Assignee: Kai-Chuan Hsieh (kchsieh)
         Status: New

** Affects: iio-sensor-proxy (Ubuntu)
     Importance: High
         Status: Fix Released

** Tags: oem-priority originate-from-1921901 somerville
ALS function lost after suspend/resume
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