Tag Archives: Linux

Fixing the Func KB-460 ‘-key

Func KB-460 keyboardI use a Func KB-460 keyboard with Nordic layout – that basically means it is a qwerty design with the Nordic keys for “åäö” on the right side as shown on the picture above. (yeah yeah Swedish has those letters fairly prominent in the language, don’t mock me now)

The most annoying part with this keyboard has been that the key repeat on the apostrophe key has been sort of broken. If you pressed it and then another key, it would immediately generate another (or more than one) apostrophe. I’ve sort of learned to work around it with some muscle memory and treating the key with care but it hasn’t been ideal.

This problem is apparently only happening on Linux someone told me (I’ve never used it on anything else) and what do you know? Here’s how to fix it on a recent Debian machine that happens to run and use systemd so your mileage will vary if you have something else:

1. Edit the file “/lib/udev/hwdb.d/60-keyboard.hwdb”. It contains keyboard mappings of scan codes to key codes for various keyboards. We will add a special line for a single scan code and for this particular keyboard model only. The line includes the USB vendor and product IDs in uppercase and you can verify that it is correct with lsusb -v and check your own keyboard.

So, add something like this at the end of the file:

# func KB-460
keyboard:usb:v195Dp2030*
KEYBOARD_KEY_70031=reserved

2. Now update the database:

$ udevadm hwdb –update

3. … and finally reload the tweaks:

$ udevadm trigger

4. Now you should have a better working key and life has improved!

With a slightly older Debian without systemd, the instructions I got that I have not tested myself but I include here for the world:

1. Find the relevant input for the device by “cat /proc/bus/input/devices”

2. Make a very simple keymap. Make a file with only a single line like this:

$ cat /lib/udev/keymaps/func
0x70031 reserved

3 Map the key with ‘keymap’:

$ sudo /lib/udev/keymap -i /dev/input/eventX /lib/udev/keymaps/func

where X is the event number you figured out in step 1.

The related kernel issue.

Changing networks with Linux

A rather long time ago I blogged about my work to better deal with changing networks while Firefox is running, and the change was then pushed for Android and I subsequently pushed the same functionality for Firefox on Mac.

Today I’ve landed yet another change, which detects network changes on Firefox OS and Linux.

Firefox Nightly screenshotAs Firefox OS uses a Linux kernel, I ended up doing the same fix for both the Firefox OS devices as for Firefox on Linux desktop: I open a socket in the AF_NETLINK family and listen on the stream of messages the kernel sends when there are network updates. This way we’re told when the routing tables update or when we get a new IP address etc. I consider this way better than the NotifyIpInterfaceChange() API Windows provides, as this allows us to filter what we’re interested in. The windows API makes that rather complicated and in fact a lot of the times when we get the notification on windows it isn’t clear to me why!

The Mac API way is what I would consider even more obscure, but then I’m not at all used to their way of doing things and how you add things to the event handlers etc.

The journey to the landing of this particular patch was once again long and bumpy and full of sweat in this tradition that seem seems to be my destiny, and this time I ran into problems with the Firefox OS emulator which seems to have some interesting bugs that cause my code to not work properly and as a result of that our automated tests failed: occasionally data sent over a pipe or socketpair doesn’t end up in the receiving end. In my case this means that my signal to the child thread to die would sometimes not be noticed and thus the thread wouldn’t exit and die as intended.

I ended up implementing a work-around that makes it work even if the emulator eats the data by also checking a shared should-I-shutdown-now flag every once in a while. For more specific details on that, see the bug.

Rpi night in GBG

pelagicore logo

Daniel talking So I flew down to and participated at yet another embedded Linux hacking event that was also co-organized by me, that took place yesterday (November 20th 2013) in Gothenburg Sweden.

The event was hosted by Pelagicore in their nice downtown facilities and it was fully signed up with some 28 attendees.

I held a talk about the current situation of real-time and low latency in the Linux kernel, a variation of a talk I’ve done before and even if I have modified it since before you can still get the gist of it on this old slideshare upload. As you can see on the photo I can do hand-wavy gestures while talking! When I finally shut up, we were fed tasty sandwiches and there was some time to socialize and actually hack on some stuff.

Embedded Linux hackers in GBG

I then continued my tradition and held a contest. This time I did raise the complexity level a bit as I decided I wanted a game with more challenges and something that feels less like a quiz and more like a game or a maze. See my separate post for full details and for your chance to test your skills.

This event was also nicely synced in time with the recent introduction of the foss-gbg mailing list, which is an effort to gather people in the area that have an interest in Free and Open Source Software. Much in the same way foss-sthlm was made a couple of years ago.

Pelagicore also handed out 9 Raspberry Pis at the event to lucky attendees.

Embedded and Raspberry Pis in GBG

Kjell Ericson's blinking leds

On November 20, we’ll gather a bunch of interested people in the same room and talk embedded Linux, open source and related matters. I’ll do a talk about real-time in Linux and I’ll run a contest in the same spirit as I’ve done before several times.

Sign-up here!

Pelagicore is hosting and sponsoring everything. I’ll mostly just show up and do what I always do: talk a lot.

So if you live in the area and are into open source and possibly embedded, do show up and I can promise you a good time.

(The photo is actually taken during one of our previous embedded hacking events.)

Embedded hacking contest #2

eneaI created another contest for the Embedded hacking event we just pulled off again, organized with foss-sthlm and Enea. Remember that I made one previously at our former hacking day?

The lesson from that time was that the puzzle ingredient then was slightly too difficult so people had to work a bit too long. It made many people give up and the ones who didn’t had to spend a significant time on solving it.

This time, I decided to use the same basic principle: ask N questions that all provide hints for the (N+1)th question, so that the first one to give me the answer to that final question is the winner. It makes it very easy for me to judge and it is a rather neat competition style game. I decided 10 questions should be enough.

To reduce some of the complexity from last time, I decided to provide the individual clues in the correct chronological order but instead add another twist: they aren’t in plain text! But since they’re chronological, the participants can go back and quite “easily” try other alternatives if there are some strange words appearing in the output. I made sure that all alternatives always have fine English alternatives so that if you pick the wrong answer it might still sound or look like English for a while…

I was very happy to see over 30 persons in the room that decided to accept the challenge. I suspect the prize did its part in attracting people to give it a go.

The rules in slightly longer terms as I put them (click it to see a higher resolution version):

the rules

And I clarified how the questions work:

the-questions

I then started my timer, and I showed all the questions on the projector to everyone. I gave them around 40 seconds per question. It thus took almost seven minutes to go through them and then I left a final slide up showing all questions:

The 10 questions

To allow readers to give this contest a go first before checking the answers. See the full answer and explanation.

A room full of competitive hackers

Linux kernel code on TV

In one of the fast-moving early scenes in episode 16 of Person of Interest at roughly 2:05 into the thing I caught this snapshot:

person of interest s01e16

(click the image to see a slightly bigger version)

It is only in sight for a fraction of a second. What is seen in the very narrow terminal screen on the right is source code scrolling by. Which source code you say? Take a look again. That my friends is kernel/groups.c from around line 30 in a recent Linux kernel. I bet that source file never had so many viewers before, although perhaps not that many actually appreciated this insight! ;-)

And before anyone asks: no, there’s absolutely no point or relevance in showing this source code in this section. It is just a way for the guys to look techy. And to be fair, in my mind kernel code is fairly techy!

Travel for fun or profit

As a protocol geek I love working in my open source projects curl, libssh2, c-ares and spindly. I also participate in a few related IETF working groups around these protocols, and perhaps primarily I enjoy the HTTPbis crowd.

Meanwhile, I’m a consultant during the day and most of my projects and assignments involve embedded systems and primarily embedded Linux. The protocol part of my life tends to be left to get practiced during my “copious” amount of spare time – you know that time after your work, after you’ve spent time with your family and played with your kids and done the things you need to do at home to keep the household in a decent shape. That time when the rest of the family has gone to bed and you should too but if you did when would you ever get time to do that fun things you really want to do?

IETF has these great gatherings every now and then and they’re awesome places to just drown in protocol mumbo jumbo for several days. They’re being hosted by various cities all over the world so often I deem them too far away or too awkward to go to, also a lot because I rarely have any direct monetary gain or compensation for going but rather I’d have to do it as a vacation and pay for it myself.

IETF 83 is going to be held in Paris during March 25-30 and it is close enough for me to want to go and HTTPbis and a few other interesting work groups are having scheduled meetings. I really considered going, at least to meet up with HTTP friends.

Something very rare instead happened that prevents me from going there! My customer (for whom I work full-time since about six months and shall remain nameless for now) asked me to join their team and go visit the large embedded conference ESC in San Jose, California in the exact same week! It really wasn’ t a hard choice for me, since this is my job and being asked to do something because I’m wanted is a nice feeling and position – and they’re paying me to go there. It will also be my first time in California even though I guess I won’t get time to actually see much of it.

I hope to write a follow-up post later on about what I’m currently working with, once it has gone public.

IDG prints lies about RMS

Joel Ã…sblom works as a “technical writer” at the Swedish “IT magazine” consortium IDG. He got assigned the job of interviewing Richard M Stallman when he was still in Stockholm after his talk at the foss-sthlm event. I had been mailing with another IDG guy (Sverker Brundin) on and off for weeks before this day to try to coordinate a time and place for this interview.

During this time, I forwarded the “usual” requests from RMS himself about how the writer should read up on the facts, the background and history behind Free Software, the GNU project and more. The recommended reading includes a lot of good info. My contact assured me that they knew this stuff and that they had interviewed mr Stallman before.

This November day after the talk done in Stockholm, Roger Sinel had volunteered to drive Richard around with his car to show him around the city and therefore he was also present in the IDG offices when Joel interviewed RMS. Roger recorded the entire interview on his phone. I’ve listened to the complete interview. You can do it as well: Part one as mp3 and ogg, and part 2 as mp3 and ogg. Roughly an hour playback time all together.

The day after the interview, Joel posted a blog entry on the computersweden.se blog (in Swedish) which not only showed disrespect towards his interviewee, but also proved that Joel has not understood very many words of Stallman’s view or perhaps he misread them on purpose. Joel’s blog post translated to English:

Yesterday I got an exclusive interview with legend Richard Stallman, who in the mid 80’s, published his GNU Manifesto on thoughts of a free operating system that would be compatible with Unix. Since then he has traveled the world with his insistent message that it is a crime against humanity to charge for the program.

As the choleric personality he is, I got the interview once I’ve made a sacred promise to never (at least in this interview) write only Linux but also add Gnu before each reference to this operating system. He thinks that his beloved GNU (a recursive acronym for GNU is Not Unix) is the basis of Linux in 1991 and thus should be mentioned in the same breath.

Another strange thing is that this man who KTH and a whole lot of other colleges have appointed an honorary doctorate has such a difficulty to understand the realities of the labor market. During the interview, I take notes on a computer running Windows, which makes him get really upset. He would certainly never condescend to work in an office where he could not run a computer that contains nothing but free software. I try to explain to him that the vast majority of office slaves depend on quite a few programs that are linked to mission-critical systems that are only available for Windows. No, Stallman insists that we must dare to stand up for our rights and not let ourselves be guided by others.

Again and again he returns to the subject that software licensing is a crime against humanity and completely ignores the argument that someone who has done a great job on designing programs also should be able to live from this.

The question then is whether the man is drugged. Yes, I actually asked if he (as suggested in some places) uses marijuana. This is because he has propagated for the drug to be allowed to get used in war veteran wellness programs. The answer is that he certainly think that cannabis should be legalized, but that he has stopped using the drug.

He confuses freedom with price – RMS never refuses anyone the right to charge for programs. Joel belittles the importance of GNU in a modern Linux system. He calls him “choleric”. He claims you cannot earn money on Free Software (maybe he needs to talk to some of the Linux kernel hackers) and he seems to think that Windows is crucial to office workers. Software licenses a crime against humanity? From the person who has authored several very widely used software licenses?

The final part about the drugs are just plain rude.

During the interview, Joel mentions several times that he is using Ubuntu at home (and Stallman explains that it is one of the non-free GNU/Linux systems). It is an excellent proof that just because someone is using a Linux-based OS, they don’t have to know one iota or care the slightest about some of the values and ethics that lie behind its creation.

In the end it leaves you wondering of Joel wrote this crap deliberately or just out of ignorance. It is hard to see that you actually can miss the point to this extent. It is just another proof what kind of business IDG is.

The reaction

Ok, so I felt betrayed and badly treated by IDG as I had helped them get this interview. I emailed Sverker and Joel with my complaints and I pointed out the range of errors and faults in this “blogpost”. I know others did too, and RMS himself of course wasn’t too thrilled with seeing yet another article with someone completely missing the point and putting words into his mouth that he never said and that he doesn’t stand for.

During the weekend I discussed this at FSCONS with friends and there were a lot of head-shakes, sighs and rolling eyes.

The two writers both responded to my harsh criticisms and brushed it off, claiming you can have different views on free vs gratis and so on, and both said something in the style “but wait for the real article”. Ok, so I held off this blog post until the “real article”.

The real article

Stallman – geni och kolerisk agitator, which then is supposedly the real article, was posted on November 15th. It basically changed nothing at all. The same flaws are there – none of the complaint mails and friendly efforts to help them straighten out the facts had any effect. I would say the most fundamental flaws ones are:

With opinions that it is a crime against humanity to charge for software Richard Stallman has made many enemies at home. In South America, he has more friends, some of which are presidents whom he persuaded to join the road to free source code.

Joel claims RMS says you can’t charge for software. The truth is that he repeatedly and with emphasis says that free software means free as in freedom, it does not necessarily means gratis. Listen to the interview, he said this clearly this time as well. And he says so every time he does a public talk.

Richard Stallman is also the founder of the Free Software Foundation, and his big show-piece is the fight against everything regarding software licenses.

Joel claims he has a “fight against everything regarding software licenses”. That’s so stupid I don’t know where to begin. The article itself even has a little box next to it describing how RMS wrote the GPL license etc. RMS is behind some of the most used software licenses in the world.

The fact that Joel tries to infer that Free Software is mostly a deal in South America is just a proof that this magazine (and writer) has no idea about for example the impact of Linux and GNU/Linux in just about all software areas except desktops.

My advice

All this serves just as a proof and a warning: please friends, approach this behemoth known as IDG with utmost care and be sure that they will not understand what you’re talking about if you’re not into their mainstream territory. They deliberately will write crap about you, even after having been told about errors and mistakes. Out of spite or just plain stupidity, I’m not sure.

[I deliberately chose not to include the full article translated to English here since it is mostly repetition.]

Back in the printing game

HP Officejet 8500AAfter my printer died, I immediately ordered a new one online and not long afterwards I could pick it up from my local post office. As I use both the scanner and the printer features pretty much I went with another “all-in-one” model and I chose an HP model (again) basically because I’ve been happy with how my previous worked (before its death). “HP Officejet Pro 8500 A910” seems to be the whole name. And yeah, it really is as black as the picture here shows it.

This model is less “photo-focused” than my previous but I never print my own photos so that’s no loss. What did annoy me was however that this model uses 4 ink cartridges instead of the 6 in my previous, but of a completely different design so I can’t even re-use my half-full ink containers from the corpse!

My new printer has some fancy features. It is one of them that I can give an email address and then print on by sending email to it. The email address then gets a really long one with lots of seemingly random letters, it is in the hp.com domain and I can set up a white-list of people (From: addresses) that is allowed to print on it via email.

It also has full internet access itself so it could fetch a firmware upgrade file and install that entirely on its own without the use of a computer. (Which made me wonder if they use libcurl, but I realize there’s no way for me to tell and of course there are many alternatives they might use.)

Driver-wise, it seems like a completely different set for Windows (hopefully this won’t uninstall itself) and on Linux I could install it fine to print, but xsane just won’t find it to scan. I intend to instead try to use the printer’s web service for scanning, hopefully that will be roughly equivalent for my limited use – I mostly scan documents, bills and invoices for my work.

Add latency to localhost

Pádraig Brady taught me a great trick in a comment to a previous blog post and it was so neat I feel a need to highlight it further as it also makes it easier for me to find it again later!

To simulate a far away server, add RTT time to the localhost device. For example if we add 100 milliseconds (which then makes 200ms ping time to localhost):

$ tc qdisc add dev lo root handle 1:0 netem delay 100msec
Restore it back to normal again with:
$ tc qdisc del dev lo root
tc qdisc add dev lo root handle 1:0 netem delay 100msec

Restore it back to normal again with:

tc qdisc del dev lo root