Bug 947437
| Summary: | Fn-F8/F9 does not change brightness | ||
|---|---|---|---|
| Product: | [Fedora] Fedora | Reporter: | Alexey Kardashevskiy <aik> |
| Component: | kernel | Assignee: | Kernel Maintainer List <kernel-maint> |
| Status: | CLOSED DUPLICATE | QA Contact: | Fedora Extras Quality Assurance <extras-qa> |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 18 | CC: | collura, gansalmon, itamar, jonathan, jskarvad, kernel-maint, madhu.chinakonda, pknirsch, rhughes, web+bugsredhat |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2013-04-12 16:47:34 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
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Description
Alexey Kardashevskiy
2013-04-02 12:24:10 UTC
It does seem as kernel regression, reassigning. Cannot be there some other service touching brightness? Like systemd (saw in google) which could do power management which could affect stuff like display dim. (In reply to comment #2) > Cannot be there some other service touching brightness? Like systemd (saw in > google) which could do power management which could affect stuff like > display dim. AFAIK systemd doesn't handle this. > 1. Press Fn-F8/F9, the brightness control appears but does not change anything, even when I press the key again. It seems that the special keys are passed correctly by the kernel. > 3. setting->power management still lets to change brightness. "echo" and "cat" work with /sys/class/backlight/acpi_video0/brightness as well. It seems the ACPI side works OK. Is the acpi_video0 the only interface under /sys/class/backlight? If it is the only interface and reacts correctly to the echo command it maybe issue of xfce4-power-manager or/and gnome-settings-daemon. In meanwhile I removed xfce4 and gnome (yum remove @xfce @gnome ; yum install @mate), I believe I eliminated those window managers and their services but it did not help with the problem. Here are the backlight interfaces: [aik@aik ~]$ ls -laR /sys/class/backlight/ /sys/class/backlight/: total 0 drwxr-xr-x. 2 root root 0 Apr 3 2013 . drwxr-xr-x. 57 root root 0 Apr 3 2013 .. lrwxrwxrwx. 1 root root 0 Apr 3 2013 acpi_video0 -> ../../devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 lrwxrwxrwx. 1 root root 0 Apr 3 2013 intel_backlight -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-LVDS-1/intel_backlight (In reply to comment #4) > Here are the backlight interfaces: > > [aik@aik ~]$ ls -laR /sys/class/backlight/ > /sys/class/backlight/: > total 0 > drwxr-xr-x. 2 root root 0 Apr 3 2013 . > drwxr-xr-x. 57 root root 0 Apr 3 2013 .. > lrwxrwxrwx. 1 root root 0 Apr 3 2013 acpi_video0 -> > ../../devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 > lrwxrwxrwx. 1 root root 0 Apr 3 2013 intel_backlight -> > ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-LVDS-1/intel_backlight I checked all three managers: xfce4-power-manager, gnome-settings-daemon and mate-power-manager. All prefer acpi_video0 over intel_backlight and it is unlikely that all three handle the backlight wrongly. So I still think there is something wrong with the kernel interface. Could you debug the brightness change (especially when reached the magic boundary 69%) and what are the corresponding values in: /sys/class/backlight/acpi_video0/actual_brightness /sys/class/backlight/acpi_video0/brightness /sys/class/backlight/acpi_video0/max_brightness I think there must be some problem (discontinuity?) there. "max" is always 100. [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/max_brightness 100 Below are values for 50, 58, 69, 80, 79, 70. The "brightness" is what the power management shows, the "actual_brightness" is the real brightness. So the magic boundary is 69%..79% of "brightness" (69% when decreasing, 79% when incresing) is actually 70% of "actual_brightness". btw! Just discovered that "power management" window does not change brightness when on battery power. However fn-f8/f9 does, within magic boundaries, of course :) [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/actual_brightness 50 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/brightness 50 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/actual_brightness 55 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/brightness 58 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/actual_brightness 65 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/brightness 69 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/actual_brightness 80 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/brightness 80 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/actual_brightness 80 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/brightness 79 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/actual_brightness 70 [aik@aik ~]$ cat /sys/class/backlight/acpi_video0/brightness 70 *** This bug has been marked as a duplicate of bug 903136 *** |