Hell Labs

Old stuff not announced before: these are a couple of small and simple GTK+ tray applications to help hobbyists installing alternative operating systems in the Eeepc and similar netbooks to show capslock or numlock status (in case the hardware lacks the appropriate LEDs) or to logout or shutdown from GUI if you’re running finit with a light desktop environment. Get the code from the git repository with git clone http://helllabs.org/git/tray.git. (You may also be interested in Metalshark’s kbdstatus, which a Xlib-based version of the original Eeepc keyboardstatus application.)

You’ll need to supply a shutdown helper script and allow it to send signals to the init process if executed from the console (registering it with pam_console, for example). The applications are GPLed, so please consider contributing back your enhancements, fixes and changes.

The traditional method of dealing with filesystem images is to mount them as loopback devices, and that is a simple, elegant and universal way to change its contents in any way you feel fit. It has the disadvantage, however, of requiring superuser privileges — which you may not have in every host you frequent, or you wisely don’t wish to grant to anyone using your machine to develop filesystem images. Christian Hohnstädt’s e2fsimage solves the problem allowing one to copy an entire subtree into a image file, but what if you want to extract, examine or manipulate arbitrary content?

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“What is nash-hotplug and why is it consuming 100% CPU?“, someone asked in a Xen-related message I found after experiencing similar problems booting Mandriva 2008.1 with finit in the Asus Eeepc. This situation seems to be especially common in different Linux distributions running as Xen guests and the usual advice is to just kill nash-plugin after the system boots. Instead of doing that ugly workaround, we decided to investigate and find out what’s happening. Whatever nash-hotplug is supposed to do, I can’t say it keeps running consuming 100% of your cpu because it’s a well-written program (notice the bizarre IPC protocol, how it tries to read from a descriptor after closing it and how easily it can get trapped in infinite loops). Use the following quick fix to avoid the problem.

• mkinitrd-6.0.34-nash-hotplug.patch

Die, nash, die.

Há algum tempo um banco passou a utilizar um sistema de verificação do computador do qual é realizado o acesso a seu sistema de internet banking, oferecendo suporte a diferentes sistemas operacionais incluindo Linux. O funcionamento desse sistema pode ser facilmente inferido com base nas chamadas feitas pela biblioteca de autenticação, dos símbolos públicos disponíveis e um pouco de dedução. O método utilizado é surpreendentemente simples tanto em conceito como em implementação; a descrição a seguir, obtida de uma breve análise das chamadas e símbolos disponíveis, pode ser de interesse dos usuários do sistema que desejem saber mais sobre os dados que são coletados de seus computadores.

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Having read the (not so enthusiastic) reviews of the first Cloudbook users, it seems that most software-related complaints of early Cloudbookers revolve around screen resolution, wifi performance and slow boot. While I offer no ready-to-use solution for these problems, here are some pointers that could help hobbyists or desperate users:

• VIA video of course won’t run with IEGD, but the (somewhat ugly) VNC-based hack for the Eeepc could work. X compositing or RandR could work depending on 3D performance, availability of RandR 1.2 for VIA graphic chips and quality compromises, but both solutions require development (i.e. possible but not available yet).
• Wifi performance issues may be related to RTL8187 rate control not working properly (it always tries to use the highest possible bitrate reducing range dramatically). Using a recent Windows driver with ndiswrapper should solve most problems, or reducing the bitrate manually should increase range using the native driver.
• Faster boot can be achived using finit (a reimplementation of the Eeepc fastinit), but some customization to finit-alt will be necessary to boot Ubuntu.

On a side note, finit-alt worked quite well booting Mandriva 2008 with Enlightenment in the Dreambook IL1, another VIA-based mini-laptop (possibly booting even faster than the Eeepc because the Intel driver for Xorg takes a while to initialize).

While I was updating the fastinit reimplementation with Metalshark’s patches, rallying enthusiast and Eeepc owner Ednilson Miura pointed me to a discussion in EeeUser about increasing screen resolution of the Eeepc display, basically by scaling down a higher resolution desktop to the native 800×480 Eeepc display. We’ve seen different approaches to solve the low resolution problem, from the traditional viewport to a larger virtual desktop to real screen rescaling (Intel has a driver-based rescaler for its Classmate PC, and there are similar resampling technologies used in other manufacturers with Eeepc-similar offerings usually with quality ranging from barely readable to unreadable). The aforementioned discussion presents a somewhat novel approach: a VNC connection to the local host. I think we could get a similar effect with a more elegant and less resource-intensive solution: X compositing. It would also be one of the first non-frivolous utilities for desktop compositing, previously used almost only for eye-candy. RandR and driver-based rescaling approaches are also discussed below.

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There is a number of updates in the Eeepc fastinit reimplementation that you might be interested in:

• It works, as confirmed by Eeepc users that tested the program.
• Metalshark fixed a bug in the reimplementation that prevented it to load the shutdown splash screen.
• Kept finit.c as an accurate reimplementation of the original Eeepc fastinit, and spawned finit-mod.c as a modified/optimized version intended to be a drop-in replacement for fastinit. A third version, finit-alt.c, contains changes to allow alternative Linux distributions to boot in the Eeepc (currently supports Mandriva 2008).

Read on for details and results of booting Mandriva 2008 on a regular (non-Eeepc) laptop using finit-alt.

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Last week I came across a no-brand, very cheap-looking USB webcam with id 0ac8:0323 and recognized by Linux as a “Z-Star Microelectronics Corp. Luxya WC-1200 USB 2.0 Webcam”, which seems to be misleading in this case.

From the USB ID it is supposed to contain a Vimicro VC0323 controller, and it was recognized as so by the GSPCA driver. This camera, however, seems to have a number of quirks that cause the driver to decode the image incorrectly: the image is fed as YUV instead of Jpeg (like the VC0321), image start offset is different from what the driver expects for VC0323 or VC0321, and finally the sensor appears to be mounted upside-down inside the camera. Read on for fix details and GSPCA patches.

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For those interested in Linux HDA sound troubleshooting, Eduardo Habkost’s Codecgraph tool finally gains a tarball and page.

Codecgraph is a tool to generate a graph based on the ALSA description of a High Definition Audio codec. The generated graph depicts the HDA codec layout and node connections, helping driver troubleshooting and maintenance. Codecgraph’s parser reads the codec description from /proc/asound/card*/codec#0 and parsed data is sent to Graphviz for actual graph generation.

I mentioned codecgraph before as the tool used to fix 5.1 sound in six and threestack ALC888-based HP systems, and recently it was used to fix 5.1/7.1 sound in the Dell Inspiron 530.

On New Year’s Eve a loose heatsink fried my old Asus motherboard northbridge, so I replaced the entire system with a nice and inexpensive Dell Inspiron 530. It’s a G33/ICH9-based system, which runs almost out-of-the box with Linux 2.6.23, except for the ethernet controller (you’ll need an upgraded e1000 driver from Intel) and HDA sound (multichannel and headphone detection not working). Use the following ALSA patch to fix both sound problems:

• Hg patch for alsa-kernel: fixes 5.1 sound and headphone detection in the Dell Inspiron 530
• Patch for Linux 2.6.23.12: same patch as above, backported to Linux 2.6.23.12

It adds the ALC888 6stack-dell mode for the Inspiron 530 and hopefully for other Dell systems based on the ALC888. The patch has already been submited upstream and should show up in the next kernel version. The patch has also been added to the current Mandriva Cooker kernel.