The Linux Experiment

Normally my laptop is on my desk at home plugged into a sound system, so I never have to change the volume. However I’m currently on holiday, so that means I’m carrying my laptop around. Last night, I had the audacity to lower the volume on my machine. After all, nobody wants to wake up their family at 2am with “The history of the USSR set to Tetris.flv”. Using the media keys on my laptop did nothing. Lowering the sound in KMix did nothing. Muting in KMix did nothing. I figured that something had gone wrong with KMix and maybe I should re-open it. Well, it turns out that was a big goddamn mistake, because that resulted in me having no sound.

It took about 30 minutes to figure out, but the solution ended up being unmuting my headphone channel in alsamixer. It looks like for whatever reason, alsamixer and KMix were set to different master channels (headphone/speaker and HDMI, respectively), thus giving KMix (and my media keys) no actual control over volume.

I went to play around with my Linux from Scratch installation after getting a working version of KDE 4.7.3 up and running. For a few days now my system has been running stood up to light web browsing use and SSH shenanigans, and hasn’t even dropped a remote connection.

This was until this evening, when I decided to reboot to try and fix a number of init scripts that were throwing some terrible error about problems in lsb_base under /lib/ somewhere. The system came back up properly, but when I startx‘d, I was missing borders for most of my windows. Appearance Preferences under KDE wouldn’t even lanch, claiming a segmentation fault.

There were no logs available to easily peruse, but after a few false starts I decided to check the filesystem with fsck from a bootable Ubuntu 11.04 USB stick. The results were not pretty:


root@ubuntu:~# fsck -a /dev/sdb3
fsck from util-linux-ng 2.17.2
/dev/sdb3 contains a file system with errors, check forced.
/dev/sdb3: Inode 1466546 has illegal block(s).

/dev/sdb3: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.
(i.e., without -a or -p options)


Running fsck without the -a option forced me into a nasty scenario, where like a certain Homer Simpson working from his home office, I repeatedly had to press “Y”:

At the end of it, I’d run through the terminal’s entire scroll buffer and continued to get errors like:


Inode 7060472 (/src/kde-workspace-4.7.3/kdm/kcm/main.cpp) has invalid mode (06400).
Clear? yes

i_file_acl for inode 7060473 (/src/kde-workspace-4.7.3/kdm/kcm/kdm-dlg.cpp) is 33554432, should be zero.
Clear? yes

Inode 7060473 (/src/kde-workspace-4.7.3/kdm/kcm/kdm-dlg.cpp) has invalid mode (00).
Clear? yes

i_file_acl for inode 7060474 (/src/kde-workspace-4.7.3/kdm/kcm/CMakeLists.txt) is 3835562035, should be zero.
Clear? yes

Inode 7060474 (/src/kde-workspace-4.7.3/kdm/kcm/CMakeLists.txt) has invalid mode (0167010).
Clear? yes


I actually gave up after after seeing several thousand of these inodes experiencing problems (later I learned that fsck -y will automatically answer yes, which means I’ve improved my productivity several thousand times!)

I was pretty quick to assess the problem: the OCZ Vertex solid state drive where I’d installed Linux has been silently corrupting data as I’ve written to it. Most of the problem sectors are in my source directories, but a few happened to be in my KDE installation on disk. This caused oddities such as power management not loading and the absence of window borders.

So what goes on from here? I plan to replace the OCZ drive under warranty and rebuild LFS on my spinning disk drive, but this time I’ll take my own advice and start building from this LiveUSB Ubuntu install, with an up-to-date kernel and where .tar.xz files are recognized. Onward goes the adventure!

Just a quick note tonight – I finally managed to get a bootable Gentoo system installed!

After my last post, things were looking pretty grim. Instead of continuing to perpetuate the recompile/reboot cycle, I decided to start fresh, in hopes that I had simply missed a step the first time around. With this in mind, I started back at page one of the Gentoo Handbook and worked my way through the entire thing.

When it came time to compile my kernel, I opted for a slightly less error-prone method, and started off by installing Genkernel, a tool that automates some of the kernel creation steps. When running it however, I was sure to pass the –menuconfig parameter, which gave me full control over what modules were included in the final product.

Next, I followed the kernel tutorials in the Gentoo Handbook and on the Gentoo Wiki Asus P5Q-E page. This ensured that I included every component that was necessary for my system.

Once I rebooted the machine, a login prompt came up the first time. Great success indeed!

One little gotcha that’s important to note at this step. On my first login, I didn’t have any network access. Two things that might help:

1. Open up /etc/conf.d/net in nano and add a line like config_eth0=”dhcp” for each network interface in your machine, where eth0 is the name of the interface. This tells the machine to use DHCP when initializing the device. On most home networks, this will get you an IP address.
2. Make sure that any required modules are loaded. I have two network interfaces. One uses the sky2 module, and the other uses skge. You can check to ensure that these are loaded with the command lsmod | grep sky2 where sky2 is the name of the module that you’re looking for. If it isn’t loaded, run modprobe sky2 to get it up and running. Note that you may need to recompile your kernel with support for the module in question if you missed it first time ’round.

Tomorrow, I’ll compile an X11 server, and hopefully get started on the GNOME desktop environment. Christ there’s still a lot to do…

Ah Linux

One website lists ten reasons to use linux my favourites of which are “Linux is easier to use than Windows” and “Linux is fun.” It is day three of the experiment and so far I haven’t installed Linux but I have taken a Dell Vostro 3350 apart about five times. I borrowed this laptop off a fellow comrade in this experiment, Jake B, as I will be sending my own netbook home this coming December.

Starting off I aimed to install both VectorLinux and Bodhi to compare them. I consider myself a relatively light computer user outside of the office and so comparing two different distributions would give me something to talk about. Alas this choice has come back to bite me in the…

I used unetbootin to begin with, on a USB key that was confirmed to be working. I then put Vector on the USB key and it brought up half a blue screen with the top of the vector logo just appearing above the black lower half of the display. After a couple of tries I figured it was corrupt files or a bad ISO so I reformated the USB in order to try Bodhi instead. Unfortunately I didn’t even get a logo this time. Next I burned a CD of Vector and got as far as the ‘find installation media’ screen but no matter how may refreshes or reloads I did it apparently couldn’t find the CD-ROM or configuration files.

From previously experiencing installers fail to find hard drives and USB keys because of the type of hard drive setting in the BIOS, I changed it from ACHI to ATA and low and behold finally some success. I managed to get the Vector installer to write partitions to the disk (using the CD at this point) after choosing the add-on applications I wanted to install. Again this failed so I tried once more with the USB key. This failed the same way except it said that it could not find live media. I even tried using the USB key and the CD together at the same time with no luck.

Switching between Bodhi and Vector in order to try and get a complete install and many, many CDs later I temporarily gave up. I downloaded a new distribution called Sabyon, a Gentoo based distro with the Enlightenment desktop environment, but alas I kept getting the same errors. I even tried Ubuntu 10.04 and Linux Mint and neither of them could not write to the disk.

Figuring it was a hard drive issue I took out the hard drive from the laptop and mounted it in an enclosure. After a quick reformat, which removed a random 500MB LVM partition that I believed to be corrupt, I put it back in the machine. Still no luck.

The errors I kept getting included disk, I/O, live media, cannot find CD-ROM, no useable media, no config file and a couple of others. Each time I tried installing it would fail at different sections of the install and the error would be different with each media used. Among all of the errors I’ve seen the main one seems to be “(initramfs) unable to find a medium containing a live filesystem”

On a whim I decided to test any other hardware errors by running diagnostics from the BIOS. No errors found. I even dug out my ancient XP Profession disc, and after a couple of BIOS changes and a couple of Blue Screens – that were my fault because I had changed the hard drive out so much – I got XP to successfully load, install, and commit changes to the hard drive.

Turning to Google, and with the help of a more advanced Linux Experiment comrade, I retried installing Linux by adding some commands to the installer boot options. Still no luck.

After more Googling I have found that there are a few possible reasons that this could be happening. I have read that it could be caused by the USB3 ports interfering with the bootable media  or that it cold be related to a CD-ROM master/slave setting. Either way, I still haven’t figured it out and I’m not willing to break someone else’s computer just to see if I can overcome this frustrating first experience with Linux. My next task is to try some ACPI hacks  and after finding this useful link, try to install the latest version of Ubuntu which seems to be compatible with the hardware of this machine. But for now its …

Windows 1 Linux 0

Men using Linux 1 Women using linux 0

Sort of a follow up (in spirit) to two of Jon’s previous posts regarding pulse audio loopback; I noticed that there was quite a bit of delay (~500ms to 1second) in the default configuration and began searching for a way to fix it. After some research I found an alternative way to achieve the loopback but with must less delay.

1. Install paman

First install the PulseAudio Manager application so that you can correctly identify the input device (i.e. your mic or line-in) and your output device (i.e. the sound card you are using).

sudo apt-get install paman

You can find the input sources under the Sources section and the output devices under the Sinks section of the Devices tab. Make note of the names of the two devices.

2. Unload any previous loopback modules

If you had followed Jon’s previous posts then you will need to unload the modules (and potentially change your PulseAudio configuration so they don’t get loaded again on next restart). This is to stop it from doubling all loopback sound.

3. Create an executable script

Create a script and copy the following command into it:

pacat -r --latency-msec=1 -d [input] | pacat -p --latency-msec=1 -d [output]

where [input] is the name of your input device found in step 1 and [output] is the name of the output device. In my case it would look like:

pacat -r --latency-msec=1 -d alsa_input.pci-0000_05_02.0.analog-stereo | pacat -p --latency-msec=1 -d alsa_output.pci-0000_05_02.0.analog-surround-51

4. Run script

By simply running the script now you should get correct loopback and with much less delay than using the default loopback module. Even better if you set this script to run at startup you won’t have to worry about it ever again.

Shortly after purchasing an xbox360, I wrote a short piece that gave instructions for forwarding your line-in audio through your pc speakers. By using this method and sharing my network connection, I’ve managed to run my xbox as a peripheral to my main computer setup, saving me space and money.

Lately however, the line-in loopback has not been working as expected. At times, it sounds like effects have been applied to the line. In particular, it sounds like somebody has applied a phaser or a delay effect to the input signal.

For the last week or so, I’ve been scratching my head about this issue, trying to figure out what part of my system may have applied effects to my loopback, but not to other audio on the system. Tonight, I was reviewing my original instructions for setting the thing up, and noticed that the module was being loaded on startup after being added to a system config file:

sudo sh -c ' echo "load-module module-loopback" >>  /etc/pulse/default.pa '

On a hunch, I took a look at the end of the file, and found the following lines:

### Make some devices default
#set-default-sink output
#set-default-source input
load-module module-loopback
load-module module-loopback

It looked like the instruction to load the loopback module had ended up in the config file twice! Because of this, the module was being loaded twice on startup.

So what does this have to do with the effects on the line? Well, if you play two copies of the same sound with a half-second gap between them, your ears will be tricked into thinking that you’re hearing one copy of the sound, but that it’s all echoey, as if a delay effect had been applied. If you repeat the experiment but this time decrease the gap between the two sounds even further, say to a few milliseconds, your ears will hear one copy of the sound with a phaser effect applied.

Essentially, when the module loaded twice, it was capturing the mix from the line-in port twice and playing back two separate copies of the audio. Depending on how close together these instances  were, the result sounded normal, phased, or delayed. I fixed the issue by removing one of the lines and then restarting the machine. This time, it started only one copy of the service, and everything sounded fine.

The moral of the story: If you’re loading modules at startup, make sure that you only start one copy of them.

At home, my setup consists of three machines -  a laptop, a PC, and an XBOX 360. The latter two share a set of speakers, but I hate having to climb under the desk to switch the cables around, and wanted a better way to switch them back and forth. My good friend Tyler B suggested that I run the line out from the XBOX into the line-in on my sound card, and just let my computer handle the audio in the same way that it handles music and movies. In theory, this works great. In practice, I had one hell of a time figuring out how to force the GNOME sound manager applet into doing my bidding.

After quite a bit of googling, I found the answer on the Ubuntu forums. It turns out that the secret lies in a pulse audio module that isn’t enabled by default. Open up a terminal and use the following commands to permanently enable this behaviour. As always, make sure that you understand what’s up before running random commands that you find on the internet as root:

pactl load-module module-loopback
sudo sh -c ' echo "load-module module-loopback" >>  /etc/pulse/default.pa '

The first line instructs PulseAudio (one of the many ways that your system talks with the underlying sound hardware) to load a module called loopback, which unsurprisingly, loops incoming audio back through your outputs. This means that you can hear everything that comes into your line-in port in real time. Note that this behaviour does not extend to your microphone input by design. The second line simply tells PulseAudio to load this module whenever the system starts.

Now if you’ll excuse me, I have jerks to run over in GTA…

After the most recently recorded podcast, I decided to take a stab at running Linux on my primary media server. The machine sports a Highpoint RocketRaid 2320 storage controller, which has support for running up to eight SATA drives. Over the course of last evening, I found out that the solution wasn’t quite as plug-and-play as running the same card under Windows. Here’s what I found out and how you can avoid the same mistakes.

Remove the RocketRaid card when installing Mint.

Make sure you have decent physical access to the machine, as the Mint installer apparently does not play nicely with this card. I replicated a complete system freeze (no keyboard or mouse input) after progressing past the keyboard layout section during the installer. Temporarily removing the 2320 from its PCI-Express slot avoided this problem; I was then able to re-insert the card after installation was complete.

Compile the Open Source driver for best results.

Highpoint has a download page for their 2300-series cards, which points to Debian and Ubuntu (x86 and x64) compatible versions of the rr232x driver. Unfortunately, the Ubuntu 64-bit version did not seem to successfully initialize – the device just wasn’t present.

A post on the Ubuntu forums (for version 9.04) was quite helpful in pointing out the required steps, but had a broken link that wasn’t easy to find. To obtain the Open Source driver, click through to the “Archive Driver Downloads for Linux and FreeBSD” page, then scroll to the bottom and grab the 32/64-bit .tar.gz file with a penguin icon. I’ve mirrored version 1.10 here in case the URLs on the HighPoint site change again: rr232x-linux-src-v1.10-090716-0928.tar.gz

The process for building the driver is as in the original post:

• Extract the .tar.gz file to a reasonably permanent location. I say this because you will likely need to rebuild the module for any kernel upgrades. I’m going to assume you’ve created something under /opt, such as /opt/rr232x.
• Change to the extraction directory and run:cd product/rr232x/linux
sudo make
sudo make install
• Reboot your system after the installation process and the kernel will load the rr232x driver as a module.

Install gnome-disk-utility to verify and mount your filesystem.

I’m not sure why this utility disappeared as a default between Mint 8 and 9, but gnome-disk-utility will display all connected devices and allow you to directly mount partitions. It will also let you know if it “sees” the RR2320 controller. In my case, after installing the driver and rebooting, I was able to click on the 3.5TB NTFS-formatted storage and assign it a mount point of /media/Raid5 in two clicks.

What’s next?

Most of the remaining complaints online revolve around booting to the RR2320 itself, which seems like more of a pain than it’s worth (even under Windows this would seem to be the case.) I personally run a separate system drive; the actual Ubuntu installation manual from Highpoint may have additional details on actually booting to your RAID volume.

I’ve yet to install the Web or CLI management interface for Linux, which should happen in the next few days. One of the really neat items about this controller is that it can email you if a disk falls out of the array, but I’ll need to get the Web interface running in order to change some outgoing mail servers.

I also haven’t done any performance testing or benchmarking with the controller versus Windows, or if there would be an improvement migrating the filesystem to ext4 as opposed to NTFS. I do plan to stick with NTFS as I’d like portability across all major platforms with this array. From initial observations, I can play back HD content from the array without stuttering while large files are being decompressed and checksummed, which is my main goal.

NOTE: ATI’s most recent drivers now include a no tearing option in the driver control panel. Enabling it there is now the preferred method.

Two of the linux machines that I use both have ATI graphics cards from the 4xxx series in them. They work well enough for what I do, very casual gaming, lots of video watching, but one thing has always bothered me to no end: video tearing. I assumed that this was due to vsync being off by default (probably for performance sake) but even after installing the proprietary drivers in the new Ubuntu 10.04 and trying to force it on I still could not get the issue to resolve itself. After some long googling I found what seems to be a solution, at least in my case. I’ll walk you through what I did.

Before you continue read this: In order to fix this issue on my computers I had to trash xorg.conf and start over. If you are afraid you are going to ruin yourself, or if you have a custom setup already, please be very careful and read before doing what I suggest or don’t continue at all. Be sure to make a backup!

1 ) Install the ATI proprietary drivers and restart so that they can take effect.

2 ) Make a backup of your xorg.conf file. Do this by opening a terminal and copying it to a backup location. For example I ran the following code:

sudo cp /etc/X11/xorg.conf /etc/X11/backup.xorg.conf

3 ) Remove your existing (original) xorg.conf file:

sudo rm /etc/X11/xorg.conf

4 ) Generate a new default xorg.conf file using aticonfig (that’s two dashes below):

sudo aticonfig –initial

5 ) Enable video syncing (again two dashes before each command):

sudo aticonfig –sync-video=on –vs=on

6 ) If possible also enable full anti-aliasing:

sudo aticonfig –fsaa=on –fsaa-samples=4

7 ) Restart now so that your computer will load the new xorg.conf file.

8 ) Open up Catalyst Control Center and under 3D -> More Settings make sure the slider under Wait for vertical refresh is set to Always On.

That should be it. Please note that this trick may not work with all media players either (I noticed Totem seemed to still have some issues). One other thing I tried in VLC was to change the video output to be OpenGL which seemed to help a lot.

Good luck!

Just a heads up: This isn’t the kind of post that contains answers to your problems. It is, unfortunately, the kind of post that contains a lot of the steps that I took to fix a problem, without much information about the order in which I performed them, why I performed them, or what they did. All that I can tell you is that after doing some or all of these things in an arbitrary order, stuff seemed to work better than it did before.

It’s funny how these posts often seem to come about when trying to get hardware related things working. I distinctly remember writing one of these about getting hardware compositing working on Debian. This one is about getting reliable audio on Kubuntu 9.10.

You see, I have recently been experiencing some odd behaviour from my audio stack in Kubuntu. My machine almost always plays the startup/shutdown noises, Banshee usually provides audio by way of GStreamer, videos playing in VLC are sometimes accompanied by audio, and Flash videos almost never have working sound. Generally speaking, restarting the machine will change one or all of these items, and sometimes none. The system is usuable, but frustrating (although I might be forgiven for saying that having no audio in Flash prevents me from wasting so much time watching youtube videos when I ought to be working).

Tonight, after some time on the #kubuntu IRC channel and the #pulseaudio channel on freenode, I managed to fix all of that, and my system now supports full 5.1 surround audio, at all times, and from all applications. Cool, no? Basically, the fix was to install some PulseAudio apps:

sudo apt-get install pulseaudio pavucontrol padevchooser

Next, go to System Settings > Multimedia, and set PulseAudio as the preferred audio device in each of the categories on the left. Finally, restart the machine a couple of times. If you’re lucky, once you restart and run pavucontrol from the terminal, you’ll see a dialog box called Volume Control. Head over to the Configuration tab, and start choosing different profiles until you can hear some audio from your system. Also, I found that most of these profiles were muted by default – you can change that on the Output Devices tab. If one of the profiles works for  you, congratulations! If not, well, I guess you’re no worse off than you were before. I warned you that this was that kind of post.

Also, while attempting to fix my audio problems, I found some neat sites:

• Colin Guthrie – I spoke to this guy on IRC, and he was really helpful. He also seems to write a lot of stuff for the PulseAudio/Phonon stack in KDE. His site is a wealth of information about the stack that I really don’t understand, but makes for good reading.
• Musings on Maintaining Ubuntu – Some guy named Dan who seems to be a lead audio developer for the Ubuntu project. Also a very interesting read, and full of interesting information about audio support in Karmic.
• A Script that Profiles your Audio Setup – This bash script compiles a readout of what your machine thinks is going on with your audio hardware, and automatically hosts it on the web so that you can share it with people trying to help you out.
• A Handy Diagram of the Linux Audio Stack – This really explains a lot about what the hell is going on when an application tries to play audio in the Linux.
• What the Linux Audio Stack Seems Like – This diagram reflects my level of understanding of Linux audio. It also reminds me of XKCD.
• Ardour – The Digital Audio Workstation – In the classic tradition of running before walking, I just have to try this app out.