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Category Archives: ubuntu

Ubuntu 14.04 Hash Sum mismatch problem.

Some update and upgrade session might corrupt the metadata of the package information in Ubuntu, more known as the “Hash Sum mismatch” error after the  apt-get update command. A workaround if the simple update command doesn’t work is you need to manually clean the package metadata record being produced, here’s how:

  1. Run these series of command on your terminal:
    apt-get clean
    rm -rf /var/cache/apt/*
    rm -rf /var/lib/apt/lists/*
  2. Then check if all works out by doing another package metadata update:
    apt-get update
  3. Done.

Full information about the discussion here: (https://gitlab.com/gitlab-org/omnibus-gitlab/issues/628)

 

 

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Fix for Elantech touchpad on Ubuntu 14.04

Since I recently got my new Lenovo G5070 notebook few days ago, I rush in to install second OS : Ubuntu 14.04, though installation process is tough, need to fix video card defaults, from fgrlx to intel graphics. Then another issue is wireless network RTL8723BE drops after each connection, but this article is about the touchpad: the ElanTech Touchpad, which by default not functioning well. Issues like there’s no switch off touchpad option in Ubuntu settings, multi-touch is not working, neither the scrolling.

Now to fix this issues, here’s the guide:

1. First, download the patch for the touchpad here.

2. Install dkms (if you haven’t done it yet)

sudo apt-get install dkms

3.  Go to the directory where you store the file and perform the following:

sudo dkms ldtarball psmouse-elantech-x551c.tar.gz
sudo dkms install -m psmouse -v elantech-x551c

4. Then reconfigure the driver

sudo rmmod psmouse
sudo modprobe psmouse
sudo update-initramfs -u -k all

5. Done

error: Diskfilter writes are not supported Ubuntu 14.04

After a clean install or upgrade from 12.04 to 14.04 on raid or lvm setup, normally you will encounter this error, which is related to the setup I mentioned. From various test, I encounter a workaround to fix this error.

Modify /etc/grub.d/10_linux 

Replace quick_boot=1 with quick_boot=0

Done.

How to re-enable Ubuntu 13.04 systray to display Pidgin and other programs.

Previously, Ubuntu tweak, myUnity and other Unity tweaking tools can provide configuration to modify current whitelist for Unity’s system tray or systray. But with recent upgrade (as usual), it was suddenly gone and nowhere to be found.

But at last, there’s a workaround (again..pfff) for this, here’s how:

1. Add this PPA and update+upgrade your Ubuntu 13.04 system.

sudo add-apt-repository ppa:timekiller/unity-systrayfix
sudo apt-get update
sudo apt-get upgrade

2. Afterwards, restart Unity, press ALT+F2 (run application), then type in  unity, press ENTER key.

3. You must have  dconf-editor to modify configuration, if not yet installed, do this:

sudo apt-get install dconf-tools

4. Open dconf-editor and navigate to  com > canonical > unity > panel  and the “systray-whitelist” should be displayed there so you can enable some apps to be able to use the systray. From the default setting, change it to ‘all’ (yes with the single quote ““character)

5. Then configure Pidgin, from Tools > Preferences. Set the Show System Tray Icon to “always

6. Done.

 

 

 

 

Allow Standard User to connect to wifi on Ubuntu

Still using Ubuntu 12.04, and one of the problem we’ve encountered is it requires normal user to authenticated the designated admin user’s password when connecting to wireless network, which in my opinion doesn’t make sense. How can a normal user access internet over wifi if they aren’t allowed to do so?

Check what google search has to offer, I finally found a fix for this. Adding policykit rules for wifi users.

Create or modify a file  etc/polkit-1/localauthority/50-local.d/52-wifi-management.pkla


$> sudo gedit etc/polkit-1/localauthority/50-local.d/52-wifi-management.pkla

and then enter the following


[Wifi management]
Identity=unix-group:netdev
Action=org.freedesktop.NetworkManager.*
ResultAny=no
ResultInactive=no
ResultActive=yes

and save on exit.

Add the user to the netdev group


$> sudo usermod -a -G ftp jerry

Restart the system and standard user should now be able to connect to wifi..

Done.

Hide network-manager applet in Ubuntu 12.04 when using ifup.

Wish to hide the nm-applet when decide to use conventional ifup instead of network-manager? Here’s how:

1. Install Gconf-Editor:

$> sudo apt-get install gconf-editor

2. Run gconf-editor and go to: Apps –> nm-applet

3. Uncheck the  setting called  show-applet

4. Done.

Ubuntu 12.04 /etc/resolv.conf 127.0.0.1 implementation with dnsmasq

On the current version of Ubuntu (12.04), you might notice that the current /etc/resolv.conf file always record a nameserver 127.0.0.1 which then resolv dns via dnsmasq, but most of the time after test few things, I found it more problematic. It always disregard my local DNS server, and goes directly to the DNS of my ISP.

If you’re having the same problem like mine, here’s a quickfix:

1. Modify the configuration /etc/NetworkManager/NetworkManager.conf

$> sudo gedit /etc/NetworkManager/NetworkManager.conf

2.  Comment the line that contain “dns=dnsmasq

[main]
...
#dns-masq

3. Then restart the network-manager

$> sudo  service network-manager restart

4. Done

 

 

Installing KVM with OpenVSwitch on Ubuntu 12.04

Here’s a good article from http://blog.allanglesit.com/, I myself tried it my in test server and it’s working great, though I’m still new with OpenVSwitch.

The article has been released for Ubuntu 12.04 system. I also found out that the KVM version currently available in Ubuntu 12.04 has better performance compare to 10.04, which I think is a good sign when planning to deploy KVM host for your VMs.

The actual URL: http://blog.allanglesit.com/2012/03/linux-kvm-ubuntu-12-04-with-openvswitch/

Done.

Show Hidden Icons from the Ubuntu’s Unity System Tray

Initially, since Ubuntu 11.04, I tried Unity several time and force myself to like it, but I can’t. Done several tweak to make it useful then, but when 12.04 came out, Unity if getting more usable and faster.

And another thing about Unity, is that I hides several icons from the default system tray, most of them place under the messaging menu icon ( the one that looks like a mail envelope), which includes pidgin, a multi-platform instant messaging client. I’ve tried several howtos to show it back to the system tray, but still I failed. Then read this acticle from ask ubuntu (here), and it works!.

Here’s how:

1. Via the console/terminal while under your login account, invoke:

$> gsettings set com.canonical.Unity.Panel systray-whitelist "['all']"

2. You can also use dconf-editor, which is included in the dconf-tool package, install it using either the “Ubuntu Software Center” or via console with the command:

$> sudo apt-get install dconf-tools

3. On dconf-editor, go to Desktop -> Unity -> Panel, and replace the value of systray-whitelist to “[‘all’]”.

4. Done.

keyboard: can’t emulate rawmode for keycode 240

Installing fresh Ubuntu 11.10 and check out what Unity and Gnome-shell has to offer, everything works great until I found something..syslog error message appears very frequent: “keyboard: can’t emulate rawmode for keycode 240“.  I remember having this problem in my previous Ubuntu 11.04 installation on my Lenovo z370 laptop, thought it’s gone back then..but to the point on installing newer kernel which is Linux kernel 3.1.

As I’m going to compile Linux kernel again to make everything work. I found a much simplier solution. Here’s how:

1. Install dkms (Dynamic Kernel Module Support Framework)

$> sudo apt-get install dkms 

2. Download the ideapad-laptop package which supposed to be fore natty narwhal but still working greate on oneiric.

$> cd ~/Downloads

$> wget https://launchpad.net/~lexical/+archive/ideapad/+build/2529783/+files/ideapad-laptop-dkms_0.1-1ubuntu1~foshan2_all.deb

$> sudo dpkg -i  ideapad-laptop-dkms_0.1-1ubuntu1~foshan2_all.deb

3. Reboot for everything to work in effect.

4. Done.

 

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