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~-[[DebianWiki/EditorGuide#translation|Translation(s)]]: none-~
----
= Redshift =

'''Redshift isn't maintained anymore and doesn't support Wayland environments. You can use DebianPkg:gammastep, a redshift fork, as an alternative.'''

For anyone who can't resist using the computer at night,
DebianPkg:redshift can seem like a godsend, turning the midnight sun
of your monitor into a cozy hearthfire.  Here (as of Jessie) are a
couple of snags to watch out for.

== Hardware cursor too hot ==

Some video drivers offload the cursor to the hardware -- your graphics
card -- because it's much faster.  But a program like Redshift works
at the software level, which means your hardware-drawn cursor will
stay white-hot no matter the time of day.  To fix that, you can tell X
to disable the hardware cursor by adding a file to
`/etc/X11/xorg.conf.d`:
{{{
    Section "Device"
    	Identifier "Screen 0"
    	Driver "nouveau"
    	Option "HWCursor" "false"
    EndSection
}}}
The identifier (name of the display device), the driver name, and even
the option syntax will vary depending on your hardware.  Here's how
you might confirm:
{{{
    $ xrandr
    Screen 0: minimum 320 x 200 ...
    $ lsmod | grep ^video
    video                  18096  1 nouveau
    $ apropos nouveau
    nouveau (4)          - NVIDIA video driver
    $ man 4 nouveau
    ... refer to xorg.conf(5) for general configuration details....
    $ man 5 xorg.conf
}}}
Changes won't take effect until you reboot (or otherwise restart the X
server).

Switching to a software cursor may turn your mouse pointer into a
glitch wand; depending on your system and your sensitivities, the
extra flickering may be an unacceptable trade-off.  Then again, some
of the side effects may be welcome: if you've ever roused a sleeping
display to find that your cursor has disappeared, switching the cursor
may be just the thing.

There are other ways to check the video driver (sifting through
`/var/log/Xorg.0.log`, for instance) and to confirm the device
identifier (running `Xorg -configure`, if possible), but let's leave
those topics to other pages and continue.

== Display manager not affected ==

If you set Redshift to start when you log in -- whether by adding it
as a start-up program in your desktop environment or with a ''`redshift &`''
in your `.xsessionrc` -- logging out can be like turning on the
floodlights.  Fortunately, some display managers let you specify
start-up programs, too.  Here's how you might arrange it with
[[LightDM]]:
{{{
    $ sudo ed -s /etc/lightdm/lightdm.conf
    ?display-setup-script?c
    display-setup-script=/etc/lightdm/redshift
    .
    wq
    $ sudo sh -c "cat > /etc/lightdm/redshift"
    #! /bin/sh

    if type redshift; then
        redshift -l -23.2:-71.3 -t 6400:3700 -r &
    fi
    $ sudo chmod +x /etc/lightdm/redshift
}}}
Rather than cramming all the options onto the command line, you may
prefer to create a system-wide configuration file instead, either at
`/etc/redshift.conf` or in `XDG_CONFIG_DIRS` if you've set them.

== See also ==

  * Bug DebianBug:791758 ("cursor is unaffected")
  * [[DebianMan:1/redshift|redshift(1)]] (option reference)