Bug 45601
| Summary: | Asus F80L: backlight brightness as a cooling_device | ||
|---|---|---|---|
| Product: | ACPI | Reporter: | max (manikulin) |
| Component: | Power-Thermal | Assignee: | Zhang Rui (rui.zhang) |
| Status: | CLOSED DOCUMENTED | ||
| Severity: | normal | CC: | lenb, rui.zhang |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 3.5.0 and earlier | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: |
gzipped acpidump
dmesg |
||
Created attachment 76781 [details]
dmesg
first, this is no ACPI fan in your laptop, or else there would be fan devices under /sys/class/thermal/ second, LCD is listed under /sys/class/thermal/. this is because it can be used for cooling by decreasing the backlight. But whether to use it or not depends on the platform thermal driver. |
Created attachment 76771 [details] gzipped acpidump On my Asus F80L laptop one of the cooling_devices reports (inverted) backlight brightness level. cat /sys/class/thermal/cooling_device2/type LCD cat /sys/class/thermal/cooling_device2/cur_state 9 # set max brightness by [Fn+F6] cat /sys/class/thermal/cooling_device2/cur_state 0 # set min brightness by [Fn+F5] cat /sys/class/thermal/cooling_device2/cur_state 15 ls -l /sys/class/thermal/cooling_device2 lrwxrwxrwx 1 root root 0 Aug 4 23:20 /sys/class/thermal/cooling_device2 -> ../../devices/virtual/thermal/cooling_device2 ls -l /sys/class/thermal/cooling_device2/ total 0 -rw-r--r-- 1 root root 4096 Aug 4 23:22 cur_state lrwxrwxrwx 1 root root 0 Aug 4 23:22 device -> ../../../LNXSYSTM:00/device:00/PNP0A08:00/LNXVIDEO:01/device:1e -r--r--r-- 1 root root 4096 Aug 4 23:22 max_state drwxr-xr-x 2 root root 0 Aug 4 23:22 power lrwxrwxrwx 1 root root 0 Aug 4 23:11 subsystem -> ../../../../class/thermal -r--r--r-- 1 root root 4096 Aug 4 23:20 type -rw-r--r-- 1 root root 4096 Aug 4 23:11 uevent Brightness level is presented in /sys/class/backlight/acpi_video0/brightness There is another file that always gives 0 /sys/class/backlight/intel_backlight/brightness Other two cooling_devices are useless since cur_state is always 0 for them cat /sys/class/thermal/cooling_device[01]/type Processor Processor No fans are detected although the laptop has one. I do not think that backlight brightness should be listed in cooling_device directory. I would prefer to have fan speed instead. acpidump > asus-f80l-acpidump Wrong checksum for generic table! Wrong checksum for generic table!