RTL8192CU Issues

Confused Configs

The TL-WN725N nano dongle is a cheap way to get 802.11n wireless connections up. However, the RTL8192CU chipset has issues under Linux.

After a whole day of trouble-shooting and digging, the best solution that I came to is this: use the driver supplied by Realtek!

First, the built-in kernel driver rtl8192cu needs to be disabled.

$ echo "blacklist rtl8192cu" >> /etc/modprobe.d/rtl8192cu.conf

Next, download, unzip and build the Realtek driver. Just run the included install.sh script.

$ bash install.sh

That’s it! All other configurations as per usual.

HP ML110 G7 Fan Noise

Confused Configs

I love the fact that HP sells servers retail in Malaysia. It’s so convenient to just pick one up from the local store instead of going through all the procedures of issuing a PO etc.

However, the ML110 G7 that I picked up a couple of weeks ago, has one rather major problem – its fans run at full speed all the time.

Granted, the server room in the office is not air-conditioned but I keep the windows open for natural ventilation. The temperature itself is just normal room temperature, as confirmed by the air-intake sensors of the server.

Although the server is the main work-horse of the entire office, it’s a small office and the work-load isn’t heavy. Most of the time, the load average is only at about 11% with the CPU clocked down to the slowest possible speed.

So, it was a pain to find that the three fans were running at a 100%:84%:10% ratio all the time. There’s no real reason to do this since the temperatures are all within a very reasonable range.

Now this wouldn’t be too much of a problem except that the fans running at those speeds sound like a jet plane taking off. It’s a small office and the noise is noticeable above the air-conditioner’s even though it sits in its own room.

It took me a little bit of sleuthing and experimenting but the final trick that did it was to simply upgrade both the BIOS (10-Aug-2012) and ILO (1.50) firmware to the latest versions.

Now, the fans only hover at a very reasonable 78%:66%:11% ratio on a very hot afternoon.

Disappearing User Dirs

Confused Configs, , ,

My current setup places the user’s home directory in a glusterfs volume. This causes problems with a recent Ubuntu 12.04 update and a user’s XDG user directories get reset to $HOME during the X11 login. It only happens for X11 logins and not shell/ssh logins.

A quick fix to this issue is to do the following:

  • Make a copy of the existing X11 session XDG configuration.
  1. # cp /etc/X11/Xsession.d/60xdg-user-dirs-update /etc/X11/Xsession.d/61xdg-user-dirs-update
  • Edit the copy to force the user directories to their defaults.
  • # nano /etc/X11/Xsession.d/61xdg-user-dirs-updateif [ -x /usr/bin/xdg-user-dirs-update ]; then
/usr/bin/xdg-user-dirs-update --force
fi

Done.

PS3 Aspect Ratio Problem

Confused Configs
Español: Logo Vectorial de YouTube

Español: Logo Vectorial de YouTube (Photo credit: Wikipedia)

After recently updating my PS3 firmware, I noticed that there was a new button in the menu – TV channels. The only option available at the moment seems to be YouTube. So, I downloaded the 22MB update and checked it out.

But for some reason, the new YouTube application ran at the wrong aspect ratio on my system. It was running in a 4:3 ratio instead of 16:9 HD ratio. My television is capable of Full-HD and I nominally had my PS3 configured to run at 1080i. Everything else seems to work fine including Bluray, games and normal video playback.

So, after a little investigation, turns out that the YouTube app runs at 720p and I had 720p disabled in my PS3 display settings. Enabling the 720p option in my display settings allowed the YouTube app to run correctly. It was odd, trying to watch 16:9 HD videos on a 16.9 TV with black horizontal bars.

So, I’ll start using the PS3 for streaming YouTube from now, on trial.

Linux on Acer RC111

Confused Configs, Electronic Kits, ,

I bought the last unit of the Acer RevoCenter RC111 at a local store a couple of days ago, for a steal – RM799 (US$263). It came with a 1TB harddisk that has Windows pre-installed on it. I wanted to install Linux on the RC111 but the Internet seems to be scant on details. So, I thought that I’d blog about how I did it.

Pre-installation
It would be a pain to install an OS onto the RC111 without a VGA port. Fortunately, the VGA port of the RC111 can be easily exposed by removing the tab covering it. Just use a sharp blade to cut the edges and press down on it slightly to break the thin strip of metal holding it in. Once that is done, the VGA port is exposed on the back.

Power up the device and you will see a minimal BIOS boot from American Megatrends. If you use a paper-clip to depress the reset button on the back of the unit when you hear a beep, the RC111 will boot from USB instead of the internal HDD.

That is the technique that I used to install Linux on the RC111.

Installation Image
It turns out that it is easier to prepare a USB installation image for Debian than it is for Centos. Therefore, I just went with Debian instead. Simply download the latest netinstall ISO and flash it onto a small USB thumb drive.

# wget http://cdimage.debian.org/debian-cd/6.0.6/i386/iso-cd/debian-6.0.6-i386-netinst.iso
# dd if=./debian-6.0.6-i386-netinst.iso of=/dev/sdb

Once that is completed, slot the USB drive into the back of the RC111 and power on the device. The indicator light on the front of the unit should flash white. The main hard-disk needs to be inserted in the RC111, otherwise it won’t boot.

At the sound of the beep, press the reset button with a bent paper clip. The indicator light on the front of the device should turn a stable purple and the RC111 will boot from the USB thumb drive.

Installation
The rest of the Debian install proceeded as normal. However, the ethernet network will not work correctly at the moment. So, it is only possible to install a bare minimal install of Debian on the device.

Post-installation
The built-in gigabit ethernet chip requires firmware that is not installed by default. It requires the firmware-realtek package that is in the non-free repository. Since the ethernet port would not work properly without the firmware, this package needs to be downloaded separately and copied over to the device and installed manually.

# dpkg -i firmware-realtek_0.28+squeeze1_all.deb

After that, the on-board gigabit ethernet will work and can be configured as usual.

All in all, it was simple enough to install an alternative OS onto the RC111. There is no reason why this should be any problem as the RC111 is basically a standard PC design with standard PC parts but with a custom BIOS.

Final Notes
At RM799 with a 1TB HDD, this is a steal and will work splendidly as a file server. I plan to stick in another 3x2TB HDD in the future for expansion.

The indicator light keeps blinking white while the machine is running. This doesn’t seem to be a problem. None of the individual HDD lights blink when in use. This is a small WMI issue that doesn’t affect the operation of each drive.

The system sometimes hangs or reboots on its own during startup. However, once it has successfully started up, it will stay running as normal.