Zeta-Puppis.com » Linux

Alsa, surround and CA0106

kratorius — Fri, 21 Mar 2008 15:36:09 +0000

This is more a remainder for me: in order to make the surround work for mp3s with the CA0106 driver with alsa (for me it’s a Sound Blaster Live! 24 bit), here’s the .asoundrc that should be used:

pcm.!dmix {
   type plug
   slave {
       pcm surround51
       channels 6
   }
}
pcm.!default {
   type plug
   slave.pcm "dmix"
   slave.channels 6
   route_policy duplicate
}

Another LinuxDay is gone

kratorius — Sun, 28 Oct 2007 17:35:17 +0000

And even this year, the LinuxDay is gone. This year we attracted more than 400 people and, as the other years, it has been an amazing experience!
So, thanks to all the visitors, to the LUGBari and to everyone else has contributed to make yesterday a great day.

Additionally, I published the slides of my yesterday’s presentation. If you’re interested, you can freely download them, but please note that they’re written in italian. You can found the PyGTK talk’s slides here, while the PyClutter’s slides can be found here (sources here and here).

Now, if you’ll excuse me, I’m going to go home and have a heart attack

kratorius — Sun, 07 Oct 2007 17:30:59 +0000

It’s 2007. And it’s October. And there’s the LinuxDay this year too.
For those who doesn’t know, the LinuxDay is a day where every LUG promote Linux and the free software philosophy to everyone who’s interested.

Last year I had a talk about Inkscape and the vectorial graphic; this year, instead, I’ll hold two talks: an introduction to PyGTK and an introduction to PyClutter.

So, if you don’t have anything to do on October 27th and you live near Bari, why don’t you join us in the LinuxDay?

(the title is a quote from a Tarantino’s film, do you like it?)

Fonera and its MTU (and the non-working wireless connection)

kratorius — Tue, 06 Feb 2007 11:14:34 +0000

A friend of mine recently bought the La Fonera (no, not really… he just had it as gift since the fon’s guys were givin’ it for free during the holidays), but he had some issues: the wireless connection wasn’t working as expected: most of the time the signal was lost and I can’t understand why since the signal’s power was strong enough. So I said to myself “that’s time to work on”. And now here I am :)

Let say that I first thought that the problem was the WPA, so I changed the authentication to WEP but the result didn’t changed.

First of all: this Fonera comes with the 0.7.1-1 (or 0.7.1 r1, as you want to call it, it’s the same) firmware, so it’s “hackable” with exploits published by several sources. But as you connect the Fonera to internet, it automatically downloads the new 0.7.1-2 firmware that apply a patch to the web interfaces so you can’t use that exploits anymore. Why do I wanted to exploit it? Well, my intentions wasn’t to exploit it to get the Fonera unlocked, I just needed a ssh connection because I wanted to understand why the wireless signal was lost.

When you exploited it (I won’t tell you how to do, google is full of this information) and finally you had access to a ssh connection, you’ll get something like this:

kratorius@becks:~$ ssh root@169.254.255.1
root@169.254.255.1's password:

BusyBox v1.1.3 (2006.11.21-19:49+0000) Built-in shell (ash)
Enter 'help' for a list of built-in commands.
_______  _______  _______
|   ____||       ||   _   |
|   ____||   -   ||  | |  |
|   |    |_______||__| |__|
|___|
Fonera Firmware (Version 0.7.1 rev 1) -------------
*
* Based on OpenWrt - http://openwrt.org
* Powered by FON - http://www.fon.com
---------------------------------------------------

root@OpenWrt:~#

The root’s password for ssh is “admin”. Well, we have access into the router, so where should we begin to look at? Obviously, let see what dmesg says. You’ll soon notice that the log is literally full of this printk’statement:

wifi0: stuck beacon; resetting (bmiss count 4)

And let see the ifconfig’s output:

root@OpenWrt:~# ifconfig
ath1      Link encap:Ethernet  HWaddr 00:18:84:18:0A:72
inet addr:192.168.10.1  Bcast:192.168.10.255  Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST  MTU:2290  Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

eth0      Link encap:Ethernet  HWaddr 00:18:84:18:0A:70
UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
RX packets:743 errors:0 dropped:0 overruns:0 frame:0
TX packets:1415 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:63354 (61.8 KiB)  TX bytes:630340 (615.5 KiB)
Interrupt:4 Base address:0x1000

eth0:1    Link encap:Ethernet  HWaddr 00:18:84:18:0A:70
inet addr:169.254.255.1  Bcast:169.254.255.255  Mask:255.255.0.0
UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
Interrupt:4 Base address:0x1000
lo        Link encap:Local Loopback
inet addr:127.0.0.1  Mask:255.0.0.0
UP LOOPBACK RUNNING  MTU:16436  Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

wifi0     Link encap:Ethernet  HWaddr 00:18:84:18:0A:71
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:2119 errors:0 dropped:0 overruns:0 frame:128
TX packets:280 errors:116 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:199
RX bytes:124155 (121.2 KiB)  TX bytes:31857 (31.1 KiB)
Interrupt:3 Memory:b0000000-b00ffffc

Do you see anything strange? Sure? Did you look at the MTU value in ath1? Yes, it’s 2290. And it’s so damn high. For an ethernet connection such value should be between 1000 and 2000 but usually for wireless connection it is set to 1492. Well change it to 1492 with:

root@OpenWrt:~# ifconfig ath1 mtu 1492

And you’ll get everything working. Obviously, you should disable the automatic firmware update, otherwise as soon as the Fonera updates its firmware you’ll get your wireless connection not working again. This is done by commenting the last line in /bin/thinclient (there’s written “. /tmp/.thinclient.sh”, just put a # in front of it). And now you can use the Fonera.

Give me more penguins

kratorius — Mon, 04 Dec 2006 13:15:46 +0000

Yesterday I were bored. So I took the linux sources and I began thinking at some interesting modify I could make.

So, ehm, well… I did something unusual. I’m proud to present the really-very-most-useless-patch-of-the-year:

Add a boot option “logonum” that allow the user to choose how many penguins to show in the framebuffer at startup. If no “logonum” is specified, it shows as many penguins as the online cpus (the default behavior).

Signed-off-by: Giuliani Vito, Ivan

The patch can be found here: http://lugbari.org/~kratorius/patches/give-me-more-penguins-2.6.19.patch
This patch applies to 2.6.19 vanilla sources.

Compile your kernel with this patch and modify your grub’s menu.lst file in this way, from something like this: kernel /boot/vmlinuz-2.6.19 root=/dev/hda6 ro vga=0x318 to to something like this: kernel /boot/vmlinuz-2.6.19 root=/dev/hda6 ro vga=0x318 logonum=5 to show 5 penguins. If you don’t tell to grub how many penguins to show, it will use the default behavior (it will show as many penguins as your online cpus).

LinuxDay 2006: the (two) week after

kratorius — Wed, 08 Nov 2006 09:44:42 +0000

So the LinuxDay is gone this year too… It has been an amazing experience, I talked about inkscape at 50-60 people. And most of them were really interested in what I was saying, and this is a real miracle :)

By the way, if you want to have a look at my slides, you can find them at http://lugbari.org/bin/view/Main/LinuxDay2006, next to my presentation’s title: “Inkscape: grafica vettoriale su Linux”.

LinuxDay 2006

kratorius — Wed, 18 Oct 2006 21:43:55 +0000

In Italy, every year, there’s a day named “LinuxDay” where we promote the use of Linux and free software. Every LUG (a Linux User Group) organize this event in their city.

I am a member of the LUG of my city (LUGBari), and this year I will talk about Inkscape. If you want to see the full program, follow this link: http://lugbari.org/bin/view/Main/LinuxDay2006

And if you want to meet me, come and join the event!

Bash tips

kratorius — Sun, 01 Oct 2006 15:30:17 +0000

Bash has some useful shortcuts that most of users are unaware of. Here I’m describing some of them that I found very very useful:

Screen clear: are you tired of typing clear all the times you want to get your screen cleared? Hint: press ctrl + L.
Reverse search: sometimes could happen that you have to retype some command you previously typed. So why don’t look for the command in the history? Press ctrl + R and begin typing the command. Bash should autocomplete it!
Command substitution: if you wrote your command and you typed a wrong letter, why to rewrite all the command? Just substitute the mistaken word. How? Use ^texttosobstitute^sobstitution. For example, if you typed apt-get updatke, you can fix it by typing as next command ^updatke^update (or simpler: ^tk^t).
Latest action: do you want to repeat the last command? Just use !!. It will (re)execute the latest command you given.
Latest parameter: and if you want to use once again the latest parameter you typed in the last command? !$ is made for you… For example, let suppose you renamed film.avi in my_new_divx.avi with mv film.avi my_new_divx.avi. If you want to see it you can just type mplayer !$. That’s all (and there’s !* that refers to all the argument passed in the previous command…).

I use these shortcuts from the time I’ve discovered them and I found them very useful (especially the number 1!). So, why don’t share such things with the other guy over here?

Incoming talks

kratorius — Sat, 16 Sep 2006 17:55:13 +0000

October will be a month full of events:

On 17th, October, I’ll be (hopefully) in Pisa attending the nss06 conference;
On 24-25-26th October I’ll attend a VoIP & Networking conference in Bari, at the Sheraton Hotel;
On 28th October I’ll hold a talk in the italian linux day, probably about vectorial graphic using inkscape.

If you’ll be in one of these events please let me know!

IBM Thinkpad R50e

kratorius — Tue, 04 Apr 2006 12:37:00 +0000

WARNING: long post
I bought my first laptop: an IBM ThinkPad R50e (I found only an italian page for this model, sorry me, but I guess there’s a translation somewhere over the IBM’s site). It has all the things I need withouth any esotic component. So I started hacking it…
The debian’s installation worked well (with testing netinstaller) and I hadn’t any problem. The only think you should keep in mind when configuring xorg is to use this in the video section:

Section "Device"
        Identifier      "Intel Corporation 82852/855GM Integrated Graphics Device"
        Driver          "i810"
        Option          "VBERestore" "yes"
        Option          "Clone" "true"
        Option          "MonitorLayout" "CRT,LFP"
        Option          "DevicePresence" "yes"
EndSection

In this way you’ll have the monitor port working (for example if you want to connect the laptop to a video projector).

The first thing I wanted to make work has been the software suspend feature (I’m not talking about the ACPI sleep state, or as it is commonly named “stand by”, but a real suspend-to-disk feature).
This can be accomplished in several ways, but usually with swsusp (that’s kernel integrated since 2.6.12 if I recall correctly) or suspend2. With a default setup it doesn’t always work; the shutdown process works well, but the resume hangs when restoring ACPI interrupts. I tried both ways, with suspend2 it never worked: when resuming it hangs at “copying original kernel back”. With swsusp you have to exclude some drivers in order to don’t always hang. First of all, remove rtc (real time clock) support. With it enabled I get crashing more often than I need. Then don’t use intelfb: although it should be supported, the swsusp with this module loaded works one out three times. I had some crashes withouth 3D acceleration enabled too (but just load i915 and everything goes ok).

Then I tried to make something cool with the thinklight. There’s already something really cool out there (rocklight over everything). But I did something cooler: every key I press makes the thinklight blink. That’s not useful, nor mindsane, but definitely geek. That’s done through a kernel patch over the keyboard driver. As soon as I finish to do some checks I’ll publish the patch here.

About the wireless card: I can’t get it in monitor mode by using vanilla kernel sources. If you want monitor mode, use ipw2200 and ieee80211 from sf.net (http://www.ieee80211.sf.net and http://www.ipw2200.sf.net) but they’re not so stable. I keep losing 10-15% of wireless packets with them. There’s not monitor mode, but since I never done wardriving (and I don’t plan to make it), I think it’s good for me.

And if you want to make something cool to show to the friends, then install fluxbox and 3ddesktop and bind /usr/bin/3ddesk to some key: that’s what will bring your friends to linux.