Tuesday, January 28, 2014

OpenSCAD for CentOS 6

I am thinking about getting a 3D Printer but before jumping in, I wanted to test out some software to see how hard it is to drive these things.


It was suggested that I check out OpenSCAD, the programmers 3D CAD program.

As usual, for CentOS-6, it did not exist. Building it was tricky and required a bit of finesse. You can download my beta build and dependencies from http://www.chrysocome.net/download

Installation Instructions

Note: gmp 5.0 is named gmp5 so it can co-exist with the system version 4.3
Note: mpfr 3.1 is names mpfr3 so it can co-exist with the system version 2.4
yum install gmp5-5.0.5-3.el6.x86_64.rpm mpfr3-3.1.0-2.el6.x86_64.rpm CGAL-4.1-1.el6.x86_64.rpm opencsg-1.3.2-6.el6.x86_64.rpm openscad-2013.06-8.el6.x86_64.rpm --enablerepo=epel

I also need to make sure that the MCAD libraries are correctly packaged. I'll try and make an updated version soon.



FreeCAD is a more traditional click and draw interface which is apparently very good and has many features. It can also be scripted with python. RPMs are available from RPM Fusion Nonfree


I need a lot of practice before I will be making any 3D objects!

Friday, January 17, 2014


On my old TV setup I used nvclock to get the NVIDIA GPU temperature and graph it using rrdtool (along with other temperatures and fan speeds).

nvclock was always a bit of a hack and does not work any more (at least, it won't do anything useful for me).

I know the nvidia-settings tool can display the temperature (and much more information) so there must be a modern way to access this data. A quick google showed up the nvidia-smi tool.

Quick and dirty,
nvidia-smi -q | grep Temperature -A 1
will show the current temperature.
        Gpu                     : 72 C

Interestingly, the output can also be in XML format. Combined with some xslt magic, it is possible to get the temperature in a more structured way.
echo '<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:output method='text'/>
<xsl:template match="/">
<xsl:for-each select="//gpu_temp">
<xsl:value-of select="."/>


' > nvidia-temp.xml
nvidia-smi --dtd > nvsmi_device_v6.dtd
nvidia-smi -q -x | xsltproc nvidia-temp.xml -

Note: Your driver might be using a different dtd version. Adjust as required. (nvidia-smi --dtd | head -1 | cut -d ' ' -f 2 will give the correct name)

If you have multiple cards and want to know which card has which temperature then you can alter the xsl to format it as you require with something like
<xsl:value-of select="ancestor::gpu/@id"/> or <xsl:value-of select="ancestor::gpu/uuid"/>
0000:04:00.0 Quadro K2000 31 C
0000:05:00.0 Quadro K2000 32 C

Friday, January 10, 2014

The new TV is almost here

Now that summer has hit, it is time to head indoors and tinker with the TV. Some clever planning when I last upgraded the disk in my CentOS-4 machine meant that the required partitions and space for CentOS-6 was available without having to alter anything.

That meant that installing CentOS-6 was relatively easy. (I did it the hard way and PXE booted off the work server via VPN). After a minimal install I configured the machine in puppet and managed to leverage most of my Linux SOE config.

After that was finished, I had a workstation but not a TV. Next step XBMC. That installed without any trouble but would not play any audio and the video kept going choppy. Not what I was expecting.

The choppy video was being caused by high load caused by the sosreport program. I don't know what crashed, and I don't much care. There is no point sending me an email about it.

I remember wrestling with this in the past without any satisfactory result. This time, rpm --erase sos did the trick. (I have to make sure puppet does not put it back.).

The audio seemed to be a problem with PulseAudio. I don't much care for this either. I have never needed it before and it does not appear to support S/PDIF / EC958 which I need so it has to go. Once again, no satisfactory instructions so rpm --erase alsa-plugins-pulseaudio seems required.

After a restart (I hate that!), all traces of pulseaudio are gone and XBMC is offering me S/PDIF again. Audio and video now working.

Next hurdle, Remote Controls. I have lots of experience with LIRC in the past because I had to make some modifications to the old version to get it to do everything I wanted. As hoped, there has been some improvement in this area but alas, also some steps backwards.

The first remote is a DVICO Fusion remote. This is a supported model but requires configuration in /etc/sysconfig/lirc and /etc/lirc/lircd.conf
/etc/sysconfig/lirc wants to know the device but it is a dynamically assigned USB HID device. This means UDEV rules ahead. It would be ideal if LIRC came with these but it seems not. Luckily I have my old EL4 rule but the new new udev uses a new format for rules. This was what I came up with in the end:
SUBSYSTEM!="usb", GOTO="end"
KERNEL!="hiddev*", GOTO="end"
ATTRS{idVendor}=="0fe9", ATTRS{idProduct}=="9010", SYMLINK+="dvico"

Now I can configure lirc and it should work reliably (unless I have two receivers, which I do but I only use one!).

Copy the lircd.conf config file from the files supplied in lirc-remotes and that is ready to go.

It seems I still need to build a Lircmap.xml file for XBMC before it will work there. Lets hope I can find a sample on the internet. Writing XML by hand is not what I call fun.

The next challenge with LIRC is my IR Blaster which controls the stereo. This uses the kernel driver called lirc_serial. I understand that this is not an enterprise solution but if lirc_dev can be in the kernel, why no lirc_serial? Well, no worries, perhaps I'll find a package which has the driver. I do require that the driver will work after a kernel update so the atrpms package is no good. And is is only version 0.8 and I am using LIRC 0.9 (may not be an issue but I want them to match).

I guess I'll just build one myself.  Enter a world of 'lirc_serial: disagrees about version of symbol' errors. Briefly, some lirc drivers are now in the EL6 kernel. lirc_serial depends on lirc_dev. The lirc_dev in the kernel is back ported so checking kernel version numbers for the correct API does not work reliably. Also, modversions seem to be cached so once the errors are fixed, the resulting module still does not work.

Finally, I abandoned the LIRC build scripts and went straight to the kernel Makefile. After tweaking a few #defines I had a working build. I then packages in into an elrepo style kmod package and now I have a working ilrc_serial driver (which you can download from http://www.chrysocome.net/download). LIRC does not come with the definition for Panasonic remotes but I have the old one on hand which still works (yay). The LIRC init script does not handle starting multiple instances so I will have to hack that up too. At least I can specify the location of the .pid file which I think was a show stopper in the old version.

The next job is to work out if I can use my IR Blaster to turn the TV on too. For a SMART TV, there are not many options for turning it on...