Shallow Thoughts
Akkana's Musings on Open Source, Science, and Nature.
Thu, 02 Jul 2009
Suspend (sleep) works very well on the dual-Atom desktop. The only
problem with it is that the mouse or keyboard wake it up. I don't mind
the keyboard, but the mouse is quite sensitive, so a breeze through
the window or a big truck driving by on the street can jiggle the
mouse and wake the machine when I'm away.
I've been through all the BIOS screens looking for a setting to flip,
but there's nothing there. Some web searching told me that under
Windows, there's a setting you can change that will affect this,
but I couldn't find anything similar for Linux, until finally
drc clued me in to /proc/acpi/wakeup.
cat /proc/acpi/wakeup
will tell you all the events that can cause your machine to wake up
from various sleep states.
Unfortunately, they're also obscurely coded. Here are mine:
Device S-state Status Sysfs node
SLPB S4 *enabled
P32 S4 disabled pci:0000:00:1e.0
UAR1 S4 enabled pnp:00:0a
PEX0 S4 disabled pci:0000:00:1c.0
PEX1 S4 disabled
PEX2 S4 disabled pci:0000:00:1c.2
PEX3 S4 disabled pci:0000:00:1c.3
PEX4 S4 disabled
PEX5 S4 disabled
UHC1 S3 disabled pci:0000:00:1d.0
UHC2 S3 disabled pci:0000:00:1d.1
UHC3 S3 disabled pci:0000:00:1d.2
UHC4 S3 disabled pci:0000:00:1d.3
EHCI S3 disabled pci:0000:00:1d.7
AC9M S4 disabled
AZAL S4 disabled pci:0000:00:1b.0
What do all those symbols mean? I have no clue. Apparently the codes
come from the BIOS's DSDT code, and since it varies from board to
board, nobody has published tables of likely translations.
The only two wakeups that were enabled for me were SLPB and UAR1.
SLPB apparently stands for SLeeP Button, and Rik suggested UAR
probably stood for Universal Asynchronous Receiver (the more familiar
term UART both receives and Transmits.)
Some of the other devices in the list can possibly be identified by
comparing their pci: codes against lspci, but not those two.
Time for some experimentation.
You can toggle any of these by writing to the wakeup device:
echo UAR1 >/proc/acpi/wakeup
It turned out that to disable mouse and keyboard wakeup, I had to
disable both SLPB and UAR1. With both disabled, the machine wakes
up when I press the power button.
(What the SLeeP Button is, if it's not the power button, I don't know.)
My mouse and keyboard are PS/2. For a USB mouse and keyboard, look
for something like USB0, UHC0, USB1.
The UAR1 setting is remembered even across boots: there's no need to
do anything to make sure the setting is remembered. But the SLPB
setting resets every time I boot. So I edited /etc/rc.local and
added this line:
echo SLPB >/proc/acpi/wakeup
Tags: linux, kernel, performance
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09:21 Jul 02, 2009
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Sun, 28 Jun 2009
Linux Planet asked me for an intro article for prospective
programmers, explaining the pros and cons of various programming
languages. Here it is:
A
Beginner's Guide to Free Software Programming Languages
Tags: writing, programming
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12:00 Jun 28, 2009
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Wed, 24 Jun 2009
I've been enjoying my
random
system beeps, different every day. At least up until yesterday,
when I didn't seem to have one. Today I didn't have one either,
and discovered that was because the beep module was no longer loaded.
Why not? Well, I updated my kernel to tweak some ACPI parameters
(fruitlessly, as it turns out; I'm trying to get powertop to give
me more information but I haven't found the magic combination of
kernel parameters it wants on this machine) and so I did a
make modules_install. And it seems that
make modules_install starts out by doing
rm -rf /lib/modules/VERSION/kernel which removed
my externally built beep module along with everything else.
I couldn't find documentation on this, but I did find
Intel
Wireless bug 556 which talks about the issue. Apparently
somewhere along the way 2.6 started doing this rm -rf,
but you can get around it by installing outside the kernel
directory.
In other words, instead of
cp beep.ko /lib/modules/2.6.29.4/kernel/drivers/input/misc/
do
cp beep.ko /lib/modules/2.6.29.4/drivers/input/misc/
Then your external module won't get wiped out at the next
modules_install.
I've let the maintainer of
Fancy Beeper
know about this, so it won't be a problem for that module,
but it's a good tip to know about in general --
I'm sure there are lots of modules that hit this problem.
Tags: linux, kernel, #tips
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09:30 Jun 24, 2009
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Sat, 20 Jun 2009
On my last Mojave trip, I spent a lot of the evenings hacking on
PyTopo.
I was going to try to stick to OpenStreetMap and other existing mapping
applications like TangoGPS, a neat little smartphone app for
downloading OpenStreetMap tiles that also runs on the desktop --
but really, there still isn't any mapping app that works well enough
for exploring maps when you have no net connection.
In particular, uploading my GPS track logs after a day of mapping,
I discovered that Tango really wasn't a good way of exploring them,
and I already know Merkaartor, nice as it is for entering new OSM
data, isn't very good at working offline. There I was, with PyTopo
and a boring hotel room; I couldn't stop myself from tweaking a bit.
Adding tracklogs was gratifyingly easy. But other aspects of the
code bother me, and when I started looking at what I might need to
do to display those Tango/OSM tiles ... well, I've known for a while
that some day I'd need to refactor PyTopo's code, and now was the time.
Surprisingly, I completed most of the refactoring on the trip.
But even after the refactoring, displaying those OSM tiles turned out
to be a lot harder than I'd hoped, because I couldn't find any
reliable way of mapping a tile name to the coordinates of that tile.
I haven't found any documentation on that anywhere, and Tango and
several other programs all do it differently and get slightly
different coordinates. That one problem was to occupy my spare time
for weeks after I got home, and I still don't have it solved.
But meanwhile, the rest of the refactoring was done, nice features
like track logs were working, and I've had to move on to other
projects. I am going to finish the OSM tile MapCollection class,
but why hold up a release with a lot of useful changes just for that?
So here's PyTopo 0.8,
and the couple of known problems with the new features will have to wait
for 0.9.
Tags: programming, python, gtk, pygtk, mapping
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19:49 Jun 20, 2009
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Fri, 19 Jun 2009
A silly little thing, but something that Python books mostly don't
mention and I can never find via Google:
How do you find all the methods in a given class, object or module?
Ideally the documentation would tell you. Wouldn't that be nice?
But in the real world, you can't count on that,
and examining all of an object's available methods can often give
you a good guess at how to do whatever you're trying to do.
Python objects keep their symbol table in a dictionary
called __dict__ (that's two underscores on either end of the word).
So just look at object.__dict__. If you just want the
names of the functions, use object.__dict__.keys().
Thanks to JanC for suggesting dir(object) and help(object), which
can be more helpful -- not all objects have a __dict__.
Tags: programming, python, tips
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11:44 Jun 19, 2009
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Wed, 17 Jun 2009
A couple of year ago I figured out how to make
custom
system beep sounds on Linux, like MacOS has done forever.
But then I changed machines and somehow never got around to setting it
up on any other machine.
But the Intel dual-Atom board doesn't seem to support a system beep --
there's no obvious place on the motherboard to plug in the connector
going to the case speaker. How odd!
With the alternative being no beep at all,
I dusted off my old blog post and went to see if
Fancy Beeper
Daemon kernel module still existed. Happily, it does, and it's
up-to-date for current kernels, so all I had to do was download the
latest and build it. Easy! Then I added "beep" to the list of
automatically loaded modules in /etc/modules,
blacklisted the pcspkr module using the
/etc/modprobe.d/00local
technique, and I was all set.
Except for the really important question: what sound to choose?
I did a little web searching for free sounds and downloaded some samples
to try out. Then I added a few bird calls from my
Stokes
Field Guide to Western Bird Songs CD,
editing them in audacity to make them shorter and
more appropriate for system beeps.
But I still couldn't decide on just one ... and why should I?
I've really been enjoying my
random
wallpaper: every time I log in, I get a different desktop background.
It's fun to see a new picture every day.
Why not do the same for my system beep?
That's no problem, using the same
randomline
script I use for wallpaper. I just put this in my .xinitrc:
$HOME/bin/mybeepd `find $HOME/Music/beeps -name "*.wav" | randomline` &
and now I get a different beep sound each day.
Yesterday it was a loon. Today it's a cow mooing.
Tags: linux, audio, desktop
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20:11 Jun 17, 2009
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Sun, 14 Jun 2009
Part 3 of "Graphical Python Programming With PyGTK"
uses object-oriented Python to clean up the code from Part 2,
and also adds handling of key events to get rid of that silly
Quit button.
PythonGTK
Programming part 3: Screensaver, Objects, and User Input
Tags: writing, python, programming
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11:18 Jun 14, 2009
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Fri, 12 Jun 2009
My last Toastmasters speech was on open formats: why you should use
open formats rather than closed/proprietary ones and the risks of
closed formats.
To make it clearer, I wanted to print out handouts people could take home
summarizing some of the most common closed formats, along with
open alternatives.
Surely there are lots of such tables on the web, I thought.
I'll just find one and customize it a little for this specific audience.
To my surprise, I couldn't find a single one. Even
openformats.org didn't
have very much.
So I started one:
Open vs. Closed Formats.
It's far from complete, so
I hope I'll continue to get contributions to flesh it out more.
And the talk? It went over very well, and people appreciated the
handout. There's a limit to how much information you can get across
in under ten minutes, but I think I got the point across.
The talk itself, such as it is, is here:
Open up!
Tags: tech, formats, open source, toastmasters
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10:37 Jun 12, 2009
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