34435a9502
Before commit 54fa0cfe4eef7e54e23380704af70ee7b65473ce, the `redshift` service was run with the environment variable `DISPLAY` set to `:0`. Commit 54fa0cfe4eef7e54e23380704af70ee7b65473ce changed this to instead use the value of the `services.xserver.display` configuration option in the value of the `DISPLAY` variable. In so doing, no default value was provided for the case where `services.xserver.display` is `null`. While the default value of `services.xserver.display` is `0`, use of which by the `redshift` module would result in `DISPLAY` again being set to `:0`, `services.xserver.display` may also be `null`, to which value it is set by, e.g., the `lightdm` module. In the case that `services.xserver.display` is `null`, with the change made in commit 54fa0cfe4eef7e54e23380704af70ee7b65473ce, the `DISPLAY` variable in the environment of the `redshift` service would be set to `:` (a single colon), which, according to my personal experience, would result in — - the `redshift` service failing to start; and - systemd repeatedly attempting to restart the `redshift` service, looping indefinitely, while the hapless `redshift` spews error messages into the journal. It can be observed that the malformed value of `DISPLAY` is likely at fault for this issue by executing the following commands in an ordinary shell, with a suitable `redshift` executable, and the X11 display not already tinted: - `redshift -O 2500` — This command should reduce the color temperature of the display (making it more reddish). - `DISPLAY=':' redshift -O 6500` — This command should raise the color temperature back up, were it not for the `DISPLAY` environment variable being set to `:` for it, which should cause it to, instead, fail with several error messages. This commit attempts to fix this issue by having the `DISPLAY` environment variable for the `redshift` service default to its old value of `:0` in the case that `services.xserver.display` is `null`. I have tested this solution on NixOS, albeit without the benefit of a system with multiple displays. |
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doc/manual | ||
lib | ||
maintainers | ||
modules | ||
tests | ||
COPYING | ||
default.nix | ||
README | ||
release-combined.nix | ||
release-small.nix | ||
release.nix |
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at http://nixos.org/nixos and in the manual in doc/manual.