[systemd-devel] Duplicate Messages in Journal

[Garry T. Williams]

On Friday, December 20, 2013 04:05:09 Zbigniew Jędrzejewski-Szmek wrote:
> On Thu, Dec 19, 2013 at 09:11:17PM -0500, Garry T. Williams wrote:
> > I see these messages in my journal:
> >
> > Dec 19 20:58:57 tfr systemd[1]: Started Load/Save Screen Backlight Brightness of acpi_video0.
> >
> > Why is the message repeated so many times?
> Usually because something resets the brightness all the time and/or
> the kernel reports brightness levels through udev events. The
> journal itself has nothing to with this.

OK, I get the bit about the journal.

I found sort of the source of this:

garry at tfr$ udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[6722.903153] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
KERNEL[6722.904958] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
KERNEL[6722.906931] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
KERNEL[6722.909084] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
KERNEL[6722.910965] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
KERNEL[6722.913139] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.913336] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
KERNEL[6722.915996] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.916708] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.916778] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.917165] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.917525] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.917986] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.918265] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
KERNEL[6722.920045] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.920410] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
KERNEL[6722.924880] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
UDEV  [6722.925270] change   /devices/pci0000:00/0000:00:02.0/backlight/acpi_video0 (backlight)
^C%
garry at tfr$

I got this output by hitting (only once) Fn+F4.

So, I guess it's the kernel reporting the event nine times.  I wonder
why that happens...

-- 
Garry T. Williams