Re: [arch-general] Nvidia backlight control - acpi_video0/brightness changes - display doesn't?

[Patrick Burroughs (Celti) via arch-general]

On Sat, 19 Nov 2016 02:00:11 -0600
"David C. Rankin"  wrote:
> [snip a whole bunch of maundering]

xrandr does not adjust the backlight. It adjusts the brightness, which
while it may have the same visible effect may have negative effects on
battery life and component wear compared to proper backlight adjustment.

acpi_backlight=vendor is the default, acpi_backlight=none is invalid.
The option you are looking for is acpi_backlight=video, which takes the
backlight control away from the vendor driver and hands it back over to
the standard ACPI backlight driver. This will generally solve the issue
you are having.

~Celti


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Re: [arch-general] Cannot no longer resolve local hostname with the new nsswitch.conf

[Patrick Burroughs (Celti) via arch-general]

On Tue, 8 Nov 2016 18:01:32 +0100
Damjan Georgievski via arch-general  wrote:

> > $ getent -s resolve hosts $(hostname)  
> 
> this should fail since you don't have the resolved service running.

nss-resolve will chainload nss-dns when systemd-resolved is not running
(see `man 8 nss-resolve`).

> but, when using `hosts: files mymachines resolve [!UNAVAIL=return] dns
> myhostname` standard resolving should then go to the dns source, and
> then to the myhostname source.

The `resolve [!UNAVAIL=return]` entry in the new default nsswitch.conf
causes NSS to /only/ continue down the list if the nss-resolve module
is /not available/; i.e., in a standard Arch setup nss-resolve will
always be queried, and pass the query on to systemd-resolved if it is
running, or fall back to nss-dns if it is not.

Nothing after the conditional will be queried — that is, in this
configuration myhostname will /always/ be skipped unless nss-resolve
fails to load. See `man 5 nsswitch.conf` for details on how the
conditional works.

There is actually a sensible reason for this: if both `resolve` and
`dns` are in there without the conditional, querying a non-existent DNS
record will cause the query to go out twice: once for nss-resolve and
once for nss-dns, because a NOTFOUND result automatically falls back to
the next item in the chain (that is, from nss-resolve to nss-dns).

Sensible solution: change the hosts line as follows.

hosts: files myhostname mymachines resolve [!UNAVAIL=return] dns

Or if you you use Zeroconf (Avahi)...

hosts: files myhostname mymachines mdns_minimal [NOTFOUND=return] resolve 
[!UNAVAIL=return] dns

~Celti


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