Solving (fixing) ubuntu 10.04 (lucid) screen flicker/distortion

I experiencing random screen distortion & flicker after upgrading to Ubuntu 10.04, I’m using Acer Notebook.
After searching in internet, there’s many forum thread & bug report discuss about this but mostly they have different hardware.
Finally I tried this method and no flickering so far.

What I do is I change my grub configuration, adding kernel parameter “i915.powersave=0”.

For Linux expert probably this is not an issue, so I dedicate this step for the newbies like :)

  1. What I do is I modify the grub configuration which is located on /boot/grub/grub.cfg (backup before you edit it)
  2. Because the access right is set to read only, let’s change it so the owner can modify it.
    > sudo chmod -c u+w /boot/grub/grub.cfg
  3. Use vi or your other prefered editor to edit it.
    > sudo vim /boot/grub/grub.cfg
  4. Locate the menuentry of your Linux. Example:
    menuentry ‘Ubuntu, with Linux 2.6.32-22-generic’ –class ubuntu –class gnu-linux –class gnu –class os {
    recordfail
    insmod ext2
    set root=’(hd0,4)’
    search –no-floppy –fs-uuid –set xxx-xxx-xxx

    linux /vmlinuz-2.6.32-22-generic root=UUID=xx-xx-xxx-x-xx ro quiet splash
    initrd /initrd.img-2.6.32-22-generic
    }
  5. Add “i915.powersave=0” to the linux kernel line as parameter. It will become:
    menuentry ‘Ubuntu, with Linux 2.6.32-22-generic’ –class ubuntu –class gnu-linux –class gnu –class os {
    recordfail
    insmod ext2
    set root=’(hd0,4)’
    search –no-floppy –fs-uuid –set xxx-xxx-xxx
    linux /vmlinuz-2.6.32-22-generic root=UUID=xx-xx-xxx-x-xx ro i915.powersave=0 quiet splash
    initrd /initrd.img-2.6.32-22-generic
    }
  6. Save & restart to check if you still experiencing screen flicker

That’s it :)
Hope it can work on other Notebook/PC

*Additional tips from tipster2010:

Thanks for this tip. It will work but after some time, flickering returns. I think I know the reason why:
1. Remember to turn off all screen saver and any power saving feature of your laptop after you did this.
2. Any time you change the theme of your desktop, the screensaver and power saving feature sometimes go back to default so you may need to manually change them again.

Thanks for this tip. It will work but after some time, flickering returns. I think I know the reason why:
1. Remember to turn off all screen saver and any power saving feature of your laptop after you did this.
2. Any time you change the theme of your desktop, the screensaver and power saving feature sometimes go back to default so you may need to manually change them again

Set up Centos yum repository to Kambing UI server (kambing.ui.ac.id)

[base]
name=CentOS-$releasever – Base
baseurl=http://kambing.ui.edu/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
#released updates
[updates]
name=CentOS-$releasever – Updates
baseurl=http://kambing.ui.edu/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
#packages used/produced in the build but not released
[addons]
name=CentOS-$releasever – Addons
baseurl=http://kambing.ui.edu/centos/$releasever/addons/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
#additional packages that may be useful
[extras]
name=CentOS-$releasever – Extras
baseurl=http://kambing.ui.edu/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5

Untuk menggunakan server kambing.ui.ac.id sebagai repository di Centos :

  • Buat file dengan extension repo di directory /etc/yum.repos.d/ (Contoh: vim /etc/yum.repos.d/Kambing-Base.repo)
  • Isi file:

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Bind JBoss to specific IP address

Simple but I think it will help JBoss newbie (like me :]) when searching the internet.

By default when you run JBoss ( ./run.sh in Linux) it will bind to localhost/127.0.0.1
This will cause the JBoss default port 8080 cannot be access from other computer, because you need to open http://127.0.0.1:8080/ instead of your IP http://<your IP>:8080/ Continue reading

Solving Pidgin cannot connect to Yahoo Messenger (YM)

Starting June 18 I started having problem connecting to YM with Pidgin.
Somehow it’s random I can connect or not.

I google and several article/forum writing that need to flush dns cache and also about several YM server cannot be accessed from Pidgin.

I try my friend advice to change YM server configuration to IP rather than domain name.
And it’s worked..
You will need to use cn.scs.msg.yahoo.com as Pager server since June 24, or you can update to pidgin 2.5.7 to solve this problem

Some people are reporting changing the Pager server didn’t solve the problem, you can follow these instruction to update your pidgin to latest version (for Ubuntu) : Updating Pidgin to latest version in Ubuntu

The steps: Continue reading

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I used to put my mysql data dir to /home/mysql, just to separated the partition so when something goes wrong or upgrading the OS I won’t lose my mysql data just because I forgot to backup it.

After I upgrade from Ubuntu 8.04 to Ubuntu 9.04 suddenly my mysql failed to start.
The strange thing the only data dir seems working is putting it on /var/lib/mysql which is the default directory for mysql data dir.

After browsing around I found out that it is apparmor that prevent mysql datadir on different directory.

So the easy way to solve this is to remove apparmor : apt-get –purge remove apparmor

Sniffing/capturing tcp data connection in Linux

When debugging my wapsite, I want to know the header from mobile HTTP request.
It’s said from some mobile-operator, they’ll include msisdn info on HTTP header.

Now tcpflow come to rescue ^^
Just type “tcpflow -ci <your-ethernet> port <port-number>”
for example “tcpflow -ci eth0 port 80″

It’ll print on console all the request to port 80 :)