There’s a new version of this post at https://www.totalnetsolutions.net/2017/09/13/kubuntu-17-04-on-dell-e5470-for-extreme-battery-life/, since it’s 4 years newer, you should head there instead.


It’s been a long time since I’ve updated my Linux buildout on this site.

I’ve recently upgraded to a Lenovo T430 (from a T500, and Dell before that). This laptop has the following hardware:

Jump to main sections with these links:
CPU Configuration
Network Configuration
Video/Bumblebee Configuration
Encryption / Security configuration
Battery saving configuration
Custom kernel .config
This is the first time in years I haven’t had a built-in 3G Modem for internet access, but with wifi tethering to my phone, I don’t think it’ll be an issue. Out of the box, everything I cared about worked. I didn’t test the fingerprint reader or the Nvidia graphics with the default install, and pretty quickly customized the system, but if you’re not into customization, rest assured, the Ubuntu team did a fantastic job on the setup.

CPU and Battery

As stated in this post from 2007, I’m a huge fan of extreme battery life. I’m still using cpufreqd, laptop-mode-tools, and checking their configuration with powertop to make sure I’m doing everything I can. I also custom-compile my kjernel, which I’ll discuss more below.

Kubuntu 12.04 defaults to the “ondemand” cpufreq driver, which is great for power savings, except that it does its speed modulation in preference of performance. That is, when the lowest speed of the processor (1.2GHz in my case) isn’t enough, ondemand immediately jumps the CPU speed to the fastest available (2.9GHz in my case). Then, when the fastest is more than required, ondemand steps off slowly. This is perfect for video and gaming applications, and most people. I, however, greatly prefer the “conservative” driver, which works in the opposite manner: when an application needs more power, the conservative driver steps up 1 CPU speed level at a time, until the appropriate CPU speed is reached. Then, when the utilization drops off, conservative immediately drops all the way to the slowest speed, to step back up again if needed.
Using cpufreqd allows me to control this even more granularily, while not getting in the way of the kernel modules. My configuration uses “ondemand” when I’m plugged in, and “conservative” when I’m on battery power. The small delay in performance is worth the added minutes in battery life, especially since most of my on-battery time is very low-demand applications.
Since sometime in 2011, Ubuntu, however, has not shipped a working cpufreqd daemon – it’s apparently broken in the upstream Debian as well, and is well documented in this Launchpad bug. So I downloaded the cpufreqd-dev source package, the patch, and rebuilt cpufreqd myself. Now that it’s working, I can use the attached updated cpufreqd.conf configuration.


Both the ethernet and wireless adapters work right on first install with Kubuntu 12.10.  The wireless uses the iwlwifi driver, and connects to my router at 104mbps.  I’m still using the script from this post to get my MTU set to 9000, rather than 1500, for jumbo frames support when in the main office network. This has a major effect on network speed for large transfers, but most networks don’t support it.h

The Wireless adapter needed no changes, and NetworkManager handles it beautifully, even when tethering to my phone.


I haven’t had any sound issues, but a few users have reported problems when using the docking station. According to this post on ThinkPad Forums, the solution is to simply edit /etc/modprobe.d/alsa-base.conf and add:
options snd-hda-intel model=thinkpad
This causes no issues on my system.


This laptop ships with two video cards, an Intel (which uses the kernel i915 driver) low-power adapter, and an Nvideo high-performance, high-power adapter. In Windows, you can click an application to switch between the two for all applications. The Nvidia adapter uses about 10W more power than the Intel card, which means using the Nvidia adapter alone halves the system’s battery life.
By default, the Ubuntu kernel enables a feature called “vgaswitcheroo” which is well documented on the Ubuntu help site. I had a hard time getting it to work with my custom kernel, though, even though it was enabled. KDE and lightdm just didn’t want to swtich the laptop panel over to the Nvidia card. This *may* have something to do with my BIOS settings, which I currently can’t change due to office IT restrictions.
There is a new project called Bumblebee, which allows the user to use the Intel card, and only turn the Nvidia on for some applications. This gives the best of both worlds for power and battery savings, but is a work-in-progress, and not all applications run under Bumblebee. I’m using the Primus additions. Installation of Bumblebee is documented here, and Primus installation is documented here. I didn’t have to make any changes to get these installs working with simple applications.

VMware Workstation 9

VMware Workstation 9, however, offered some interesting challenges with Bumblebee. Out of the box, Vmware Workstation 9 installed (even with my custom kernel), and ran great, but would always give a warning that 3D acceleration was not available, which I expected while using the Intel card. However, Bumblebee has some limitations which mean it can’t run VMware workstation by default. I wrote a script to handle this, which I wrote up last night. I’m using a lot of work of others, so follow the links on that page to cmillersp’s post on the VMware Community Forums.

Encryption and Security

During installation, I chose the option to use an encrypted LVM volume. This uses DM-Crypt to encrypt the full HDD, so that it has to be unlocked at boot time. The Kubuntu installer seems to forget this fact, so it also asks you to set up ecryptfs private home directories, which is NOT neccessary for a single-user laptop, since the whole OS is already encrypted. The only oddity with dm-crypt is that sometimes the splash screen prompt to unlock the computer doesn’t show. If I just wait for disk activity to disappear, and have a blank screen, I can just type the passphrase, and it’ll still unlock successfully.

I don’t have the fingerprint reader set up, but if I do, I’ll update this post.

Battery and Power Savings

First, I use the configuration in the CPU Configuration section above for cpufreqd. Then I use laptop-mode-tools to set other configuration settings. I’ve attached all the files I have modified here, and it’s fairly power-saving aggressive. The only thing I should do, but don’t, is to disable the bluetooth adapter when I’m on battery, since it uses 1W just for the adapter. However, I have bluetooth headphones and a bluetooth mouse, which is why I have the bluetooth adapter in the laptop to begin with, so disabling it removes some critical functionality. I DO have it set to autosuspend, which is a little annoying when I go back to the mouse after 5 seconds of inactivity, but the annoyance is worth the savings, especially when I’m writing a long post like this.
All of these go in /etc/laptop-mode/conf.d :

With these settings, I was able to write this whole post, with the bluetooth mouse connected, running at an average of 13.2W. In 3.4 hours (I was doing other tasks, including feeding and changing my napping baby), I used 41% of my 93.6Wh battery. If I were to take this on a plane, I’d kill the wireless and bluetooth for probably another 2W savings, but I’d do that by hand.

Kernel Configuration

I have been building a custom kernel for my laptop for about 6 years now. The default Ubuntu image uses “generic-x86_64” for the processor family, but all of my laptops are “Core2 / Newer Xeon”. Just making that single change to my kernel results in about 0.5W-1W less power consumption, due to the increased efficiency gained by the kernel knowing about the new processor registers and commands that aren’t available to older processors. This greater CPU efficiency also means lower temperatures, and therefore lower fan speed.

My kernel configuration is attached here. Build it by following the instructions at the Ubuntu Help site

sudo apt-get install linux-kernel-devel fakeroot kernel-wedge build-essential
sudo apt-get install linux-source
sudo usermod -a -G src YOUR_USERNAME

Now log out and back in, so that you’re a member of the “src” group.

cd /usr/src
sudo chown -R $USER:src .
tar -jxf ./linux-source-3.5.0/linux-source-3.5.0.tar.bz2
ln -s linux-source-3.5.0 linux
cd linux
wget http://www.totalnetsolutions.net/wp-content/uploads/2012/12/rob-config-20121204c.txt
mv rob-config-20121204c.txt .config
make oldconfig
make menuconfig

Make any changes you want in here, then exit and save

fakeroot make-kpkg --initrd --append-to-version=.20121204c kernel_image kernel_headers

You’ll get 2 DEB files in /usr/src that you can then install and boot to. the “append-to-version” I use as a dating system for my kernels. “20121204c” means the 4th kernel attempt on December 4th, 2012, the day I recieved this laptop.

All Modified Files

Laptop-mode-tools config:
All of these go in /etc/laptop-mode/conf.d :
Other configs:
custom kernel .config.

I have a new Lenovo T430 with Nvidia/Intel hybrid graphics. The Intel card is for power saving, the Nvidia card for performance. The easiest way to handle this setup is to just choose the correct card on bootup, but this is inconvenient. Bumblebee provides a way to use the Intel card most of the time, but use the Nvidia for high-performance tasks such as games, and ONLY for those apps. Once it’s set up, it works pretty well, except for a few apps that require additional tweaking, such as Steam, or Wine.

One of the apps that requires tweaking is VMware Workstation (I’m running WKS 9). cmillersp provided a great write-up on the VMware Communities, which is what I set up on my system. VMware Workstation runs great – I can load OpenGL 3D apps in VMs and everything runs fantastic.

Except that I run VMs all the time, and using the Nvidia card all the time kills the performance benefit of the Intel card twice: once because I’m using the Nvidia card, and once again because BOTH GPUs are running at the same time. So I wanted a way to dynamically choose which card to run VMware under, based on whether I was on AC power or battery power.

The result is the attached script below, which I’ll be submitting to the Bumblebee wiki / project, as well as the VMware forums. This is version 1, which works as follows:

  1. Must be installed by “sudo ~/bin/vmware –install” – it will make the cd /usr/lib/vmware/bin; mv vmware-vmx vmware-vmx.real and then do the script creation at /usr/lib/vmware/bin/vmware-vmx, so that it’s a single portable script.
  2. Takes several options to force using the Nvidia card or not
  3. If no force option is applied, automatically determines AC adapter state or battery charge/discharge state
  4. Based on the above, decides whether to launch /usr/bin/vmware normally, or via the instructions from cmillersp

I’ve done some additional work to make it run via either “primusrun” or “optirun”. Optirun is much slower, but at least functional with fewer installs. I hope this is useful to someone else!

Edit: 2012-12-17 – v1.1 added gksu auto-detection
Edit: 2014-01-08 – Moved to github repo: github.com/docsmooth/vmware-bumblebee

Joe and Jorge posted these back in 2005 and 2006, but they’re impossible for me to find in Google lately, possibly because of age:


In order to move an object in DS, you need the following three permissions:
1) DELETE_CHILD on the source container or DELETE on the object being moved
2) WRITE_PROP on the object being moved for two properties: RDN (name) and
CN (or whatever happens to be the rdn attribute for this class, i.e. ou for
org units).
3) CREATE_CHILD on the destination container.

Dmitri Gavrilov
SDE, Active Directory Core
This posting is provided “AS IS” with no warranties, and confers no rights.
Use of included script samples are subject to the terms specified at

But, what, specifically does that mean?

  1. To provide these rights, after delegating control for the Creation and Deletion of the object (Computer/User/etc.), open ADSIEDIT.MSC and navigate to the OU in question.
  2. Right-click the OU and choose “Properties”
  3. Click on the “Security” tab.
  4. Click the “Advanced” button.
  5. Click the “Add” button to add a new security right.
  6. Enter the group you want to delegate the control to and click “OK”
  7. Choose the “Properties” tab.
  8. In the pulldown, choose “Descendent Computer Objects”
  9. Grant:
  1. Read and Write canonicalName
  2. Read and Write name
  3. Read and Write Name

I was troubleshooting a problem with some other vendor’s software tonight on a Red Hat Enterprise Linux 5.3 system.  We were able to reproduce the problem in the lab,  which was a huge boost to production, and insight, but we hit a wall when we got this error:

GNU gdb (GDB) Red Hat Enterprise Linux (7.0.1-42.el5)
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
Reading symbols from /opt/vendor/redacted/process...(no debugging symbols found)...done.
Attaching to program: /opt/vendor/redacted/process, process 16492
ptrace: Operation not permitted.

The weird thing is that we were running gdb as root, and it was 2.6.18. In the latest Ubuntu versions, a security hardening option has been added to the kernel to limit gdb (profiling, particularly, which gdb requires) to only being run on child processes. Since this was Red Hat Enterprise Linux 5.3, it didn’t have this option.

Well, it turns out that explaining it to #gdb on Freenode pointed us to the solution: a parent process had been attached to via “strace -f”. Since only one profiling process can run on any program at one time, the parent process’s “strace”, by following all forks with the “-f”, blocked out our “gdb” from attaching to the child. Simply adding 1 line:

pkill strace
gdb /opt/vendor/redacted/process `pgrep process`

to our debugging solved the mysterious “ptrace: Operation not permitted.” error which was showing me no results in web searches. FYI: this absolutely will block gcore in the same way.

Many are the times we’ve run into DNS configuration problems with Microsoft AD.  After being asked for advice a few more times than normal this year, I’ve pulled together several emails for this list of “Troubleshooting Microsoft AD-integrated DNS” highlights below.  We’ll first cover the generic topics of checking the configuration of your server configuration,  then the configuration of the zones themselves. For each topic, we’ll do a checklist followed by an explanation.

Server configuration:


  1. Is the server (Windows 2003 or higher) pointing to itself for primary DNS in the network configuration?
  2. If a standalone DC: Does the server have *no* secondary DNS in the network configuration?
  3. If there are multiple DCs: Does the server list only other DCs in the secondary DNS server list in the advanced network configuration?
  4. Does the server have proper forwarders in the DNS server configuration (to the parent domain or to the ISP, but not both)?
  5. In a command prompt, run the following:
    ipconfig /registerdns
    net stop netlogon
    net start netlogon
  6. Read DNS and System logs to make sure there are no issues being reported.
  7. wait 20 minutes


One of the major problems we run into is that customers will put the ISP DNS servers in the network configuration on the DC, not in the DNS Forwarders list in the DNS Server configuration.  The DC *is* a DNS server.  It needs to talk to itself, so that it can register crucial DNS settings in its own database.  If its own database can’t find the information requested (such as www.google.com), then the DNS Server service is responsible for looking that data up, and then caching it so that it’s readily available for other clients, too.  This misconfiguration also has the problem of generating DDNS update requests back to the ISP DNS servers, which are ignored at best, and a security leak at worst (like for military/government installations).

I like to tell my Unix customers “the first rule of administering Active Directory is to go get another cup of coffee.” This forces them to take their hands off the keyboard and wait for cross-site replication (hopefully) before making another change.  It’s a good reminder for the seasoned Windows admins, as well.

Zone Configuration

Reverse Lookup Zones

We’ll cover reverse lookup zones before forward lookup zones, for two reasons: 1) customers screw up reverse lookup configuration much more often than forward lookup configuration ; 2) no SRV records in Reverse zones (normally).


If you have non-Microsoft DNS servers or multiple AD domains in your environment

  1. Does the server have reverse DNS zones defined?
  2. Does any *other* server (in the DNS Forwarders configuration list) have the same reverse DNS zone defined?
  3. Do the defined reverse zones allow “unsecured dynamic updates”?
  4. Are all IP subnets in your network defined as reverse DNS zones on the primary DNS servers (the last forwarders in the network before the ISP)?
  5. Do you have aging and scavenging turned on in the server settings?  If so (you should), do you have all clients automatically renewing their records (Windows clients will by default)?

If you only have a single AD domain, or no non-Microsoft DNS servers

  1. Does the server have reverse DNS zones defined for all IP subnets (including IPv6) in your network?
  2. Do those reverse DNS zones allow dynamic updates?
  3. Is aging of old records enabled with sane no-refresh and refresh values  in the reverse zones?


Each DNS Zone is a database.  There can only be one authoritative owner of the database, defined by the SOA record on the Zone.  Any other DNS servers get their information from this SOA, either by normal queries, or by zone transfer (AD replication does a kind of zone transfer).  If two servers are set up with the same zone (create 0.168.192.in-addr.arpa reverse DNS zone in dns1.contoso.com and ns1.worldwidetoys.com, for example), then there is no mechanism to transfer the information between those two servers.

For example: any individual client will only talk to the DNS server it’s configured to talk to (client1.contoso.com gets its DNS info from dns1.contoso.com and winxp1.worldwidetoys.com gets its information from ns1.worldwidetoys.com). Each client will also send updates only to its own DNS server.  This means that client1.contoso.com will register its IP with dns1.contoso.com, and winxp1.worldwidetoys.com will register its IP with ns1.worldwidetoys.com.  These two records will never be synched between dns1.contoso.com and ns1.worldwidetoys.com.  Therefore, when winxp1.worldwidetoys.com asks ns1.worldwidetoys.com “who has”, ns1.worldwidetoys.com will answer “nobody!”.

The DNS admin must fix this problem by manually registering all of the records from ns1.worldwidetoys.com in the zone stored in dns1.contoso.com, deleting the 0.168.192.in-addr.arpa zone from ns1.worldwidetoys.com, and then setting up a forwarder or conditional forwarder to dns1.contoso.com.  Now, that same query results in ns1.worldwidetoys.com looking in its own database, finding no answer, and reaching out to its forwarders to ask, “who has”.  Similarly, when winxp1.worldwidetoys.com goes to register, it is directed, via the SOA record, to send that registration to dns1.contoso.com.  This is why reverse zones often need to allow unsecured dynamic updates.

Forward Lookup Zones

I have a customer who needs this much data now – I’ll follow up with the Forward Lookup zones in a separate post later this week.

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