blog.crox.net (Entries tagged as debian)

Disable WiFi Power Management on Raspbian 12 (Network Manager)

nospam@example.com (crox) — Fri, 15 Aug 2025 22:48:00 +0000

8 years later there are still issues on Raspberry Pi / Raspbian with WiFi power management causing disconnects and generally bad performance.

I've found a reliable method to disable WiFi Power Management for the on-board WiFi chip (brcmfmac) here: NetworkManager WiFi Power Saving.

libheif1 >= 1.18 on debian 12 bookworm (installing packages from backport in debian stable)

nospam@example.com (crox) — Fri, 02 May 2025 18:08:00 +0000

Add this line to /etc/apt/sources.list:

deb http://deb.debian.org/debian bookworm-backports main

Run:

# apt-get update
# apt install -t bookworm-backports libheif1

This solves the issues encountered when decoding HEIF (.heic) files produced by iPhone / iOS 18, causing for instance rendering in Nextcloud to fail.

This page has more details on using Backports.

BackupPC - binary garbage in XferLog.z / XferLog.z getting huge

nospam@example.com (crox) — Fri, 30 Dec 2022 18:32:00 +0000

I run a BackupPC instance that is still on Debian 10 / buster. The latest rsync package for Debian 10 has version number 3.1.3-6.

I recently noticed infrequent issues when backing up hosts that are either on Debian 11 / bullseye, or on Ubuntu 22.04 (which both ship rsync 3.2.3). The symptoms are as follows:

- backups take much longer than usual
- XferLog.z starts "normally", but after a certain point contains a lot of binary garbage, and gets much bigger than usual (hundreds of MB, or even in one case up to 12 GB)

After investigating and looking for information online, I came across these bug reports, which contain the explanation as well as a workaround: Debian Bug report #969463 and BackupPC issue #369.

=> The issue is caused by a combination of a change of default behaviour introduced with rsync 3.2.3, and a bug in File::RsyncP.

The solution that works for me (pending an update to Debian 11 and BackupPC 4) is to add the following line in the individual server config for each of the affected hosts:

$Conf{RsyncArgsExtra} = ['--no-msgs2stderr'];

Find large files in a BackupPC transfer log (sort files in XferLOG by size)

nospam@example.com (crox) — Sat, 13 Mar 2021 14:40:00 +0000

When your backups suddenly takes much longer to complete, it could be because large files that were previously excluded from the backup were renamed or relocated elsewhere. In order to identify those files, or just to sort the list of files by size, I use the following code (bash):

cd /tmp/
BackupPC_zcat /var/lib/backuppc/pc/mypc/XferLOG.99.z > xlog
for S in `cat xlog | sed -e 's/^[^/]*\/[0-9]*[ ]*//' | cut -f1 -d\  | egrep '^[0-9]+$' | egrep '[0-9]{9,}' | sort -n | uniq ` ; do fgrep " $S " xlog ; done

This will show the list of files bigger than 99999999 bytes (100 MB). Remove "| egrep '[0-9]{9,}'" to just list all instead.

Note: on Debian, BackupPC_zcat is in /usr/share/backuppc/bin/. I've added a symlink in /usr/local/bin/ so that I don't need to look for it every time.

Grafana PNG export on headless Debian server (phantomjs / render fails with "404 page not found")

nospam@example.com (crox) — Tue, 26 Dec 2017 20:38:00 +0000

If it still fails after you've set "root_url" to the correct value in grafana.ini, you might want to check whether you can run phantomjs from the command line.

If you get "QXcbConnection: Could not connect to display / PhantomJS has crashed", then the explanation is here: Debian Bug #817277.

To fix it, I installed xvfb (apt-get install xvfb), and edited /usr/bin/phantomjs so that the last line now looks like this:

exec "/usr/bin/xvfb-run" --server-args="-screen 0 640x480x16" "/usr/lib/phantomjs/phantomjs" "$@"

How to solve Edimax EW-7612UAn v2 (7392:7822) power management issues on Raspberry Pi (Raspbian WiFi disconnect)

nospam@example.com (crox) — Sun, 12 Nov 2017 19:04:00 +0000

On Raspbian, you don't need to install the 8192cu driver manually, as it comes with the distribution

To avoid disconnection issues, you need however to disable power management. This needs to be done in two places. First, this is what I have in /etc/modprobe.d/8192cu.conf:
```
options 8192cu rtw_power_mgnt=0 rtw_enusbss=0
```

This alone did not prevent the issue. I also had to add this entry to /etc/network/interfaces:

auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
wireless-power off
iface default inet dhcp

Sources: https://github.com/xbianonpi/xbian/issues/217, https://www.kuerbis.org/2016/03/raspberry-pi-3-kurztipps-wlan-sleep-mode-verhindern/

Using a Raspberry Pi running raspbmc to sync Fitbit One with galileo (fitbit linux sync)

nospam@example.com (crox) — Sat, 05 Apr 2014 11:47:47 +0000

(it should work with any other Debian-based Raspberry Pi distribution and all newer Fitbit devices that use BLE)

sudo -i
apt-get update
apt-get install python-pip
pip install galileo
galileo

You can then use cron or a simple shell script to periodically run galileo.

vim instead of nano (Ubuntu / Debian)

nospam@example.com (crox) — Sun, 19 May 2013 20:52:22 +0000

apt-get install vim
update-alternatives --config editor

raspbmc - getting rid of iptables

nospam@example.com (crox) — Thu, 04 Apr 2013 20:39:00 +0000

I don't need a firewall on my Raspberry PI which runs XMBC (raspbmc distribution) - it's in a dedicated subnet behind a firewall. Furthermore, there are several reports of iptables having an impact on the performance of network playback, causing buffering issues (although I didn't do any benchmark myself).

I modified /etc/network/if-up.d/secure-rmc by adding "exit 0" right at the beginning like this:

#!/bin/bash

exit 0

dec_to_bin() {
...

And then I ran:

apt-get remove iptables

This was followed by a reboot.

nb: the secure-rmc file appears to be a raspbmc addition, and it could probably just be deleted instead.