Cover photo
Greg Kroah-Hartman
Works at Linux


Greg Kroah-Hartman

Shared publicly  - 
We haven't talked much about kdbus recently, but that doesn't mean we weren't busy. The kernel module has matured and provides ABI stability now, we've spent many long evenings on improving the user-space compatibility layer to dbus1, and we've reached out to start converting the other bus-libraries.
My system has been running kdbus just fine for over half a year now. There are, occasionally, some hiccups we have to fix, but the overall experience is pretty neat.

Anyway, why am I writing this: If you run on Fedora Rawhide, you can now test kdbus by simply adding `kdbus=1` to your kernel command-line (or `kdbus=0` to disable it; which is still the default). If you run other distros, we have created a page that describes the required steps shortly [1].

If you have some spare time, we'd greatly appreciate if developers would give this a try. It works fine for us, but there are thousands of other dbus applications in the wild which might not work with the compat layer. Any feedback is highly appreciated! And, if you attend the upcoming systemd conference [2], I'd gladly return the favor with some beer! :)

david@david-t2 ~/dev/kdbus $ busctl monitor Monitoring bus message stream. ‣ Type=signal Endian=l Flags=1 Version=2 Priority=0 Cookie=-1 Sender=org.freedesktop.DBus Path=/org/freedesktop/DBus Interface=org.freedesktop.DBus Member=NameOwnerChanged Monotonic=21122678158 Realtime=1438248540378044 ...
7 comments on original post
Jeshwanth Kumar N K's profile photoDrew Fustini (pdp7)'s profile photoChristian Andersson's profile photoTom Keidar's profile photo
+David Herrmann: that's why I said recommendation, but the spec would be even better, indeed. Let me know if I can help in any way.
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
If you invent something new, one of the hardest parts is to convey your concept. In the case of kdbus, I meet a lot of people who don't have a clue what it actually does. On the other hand, most people seem to be pretty familiar with AF_UNIX. Hence, I went ahead and tried to describe the very fundamental concept of kdbus, by "speaking" AF_UNIX.

I hope this makes people re-evaluate their position, if they read some premature judgement about kdbus on news media or forums. I don't believe kdbus is something radically new, nor is it a huge code-base. I much rather believe we just picked the parts of existing features we needed, and formed a fresh new interface that should serve DBus' needs for the years to come.
2 comments on original post
Atanas Beloborodov's profile photoDjalal Harouni's profile photoPeter Senna Tschudin's profile photoHoang Tran's profile photo
I'll have to-reread.  I was half awake.  =)
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
As announced yesterday at LinuxCon Japan at the LTSI talk by longtime kernel contributor and NEC executive Tsugikazu Shibata, 4.1 is going to be the next long term kernel that I support for this year.
“Linux4.1 is LTS version of 2015!!”
Nikolay Nikolaev's profile photoAirken Lin's profile photo
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
First live demo of a working unipro switched phone with the greybus protocol just happened. A camera was added to the phone after it booted and it took a picture. Android becoming a dynamic system, it's about time :-)
Eduardo Valentin's profile photoJeshwanth Kumar N K's profile photoKrzysztof Wilczynski's profile photoDjalal Harouni's profile photo
+Nick Johnson I think I know the status of USB on Android :)

As for "what's so special" about this, this is a hardware protocol that prior to this implementation, was static, point to point, and not changeable.  Unipro has been around for about a decade in systems like phones, for the camera and displays and other things.  This phone turns Unipro into a routable and hotplugable system, fully dynamic.  It's way faster than USB and can be peer-to-peer if wanted (the main CPU doesn't get involved after the routes are set up), which is impossible on USB, and a major pain on PCI to get right (not to mention the security issues of PCI, which this system solves completely). It also allows you to tunnel a bunch of "legacy" hardware protocols across it like USB, serial, GPIO, I2C, I2S, SPI, and others, in ways that is almost transparent to the kernel drivers (totally transparent to USB and serial, 20-30 lines needed for other drivers), or export those protocols out to userspace applications so you can control your spi-based sensor module directly from an Android application, no special kernel support needed.

I can go on, and actually will in a few days at LinuxCon Japan with a talk all about this at that conference, so see the video of it if you are curious.

Oh, and all of the hardware, firmware, mechanical, and of course kernel code, is all open source, as well as the protocol specification, and you can look at it today and watch it evolve in our github repos.  No other project has ever done that before that I know of.

+Thomas Petazzoni yes, the work here is taking all of the things we did 10 years ago to make Linux the kernel dynamic, and make Android dynamic.  As you know, right now Android is very static, almost the whole system definition is determined at build time, and a few things at boot time, and almost nothing at run-time.  I don't think there's ever been a demo of Android adding a CSI camera to the system after it had booted.

The work here will eventually make Android fully dynamic, with devices being able to be added or removed on the fly.  You want 6 batteries, and then later remove 3 of them?  You want 2 wifi devices? Handle different cameras with different resolutions?  All will eventually not be an issue at all.  That will make it even easier to get an Android system up and running for the "old static" type machines as well, just like the work we did in Linux to make everything dynamic made all of the "static" laptops and servers trivial to setup properly.

In short, this is good shit.
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
eBPF is scary powerful, hopefully more people learn about it through example scripts like these.
I've taken one small step with eBPF, but it heralds one giant leap for Linux tracing. # ./bitehist Tracing block device I/O... Interval 5 secs. Ctrl-C to end. kbytes : count distribution 0 -> 1 : 3 | | 2 -> 3 : 0 | | 4 -> 7 : 3395 |************************************* | 8 -> 15 : 1 | | 16 -> 31 ...
Arun Bhanu's profile photoAsai Thambi S P's profile photoHenry Kleynhans's profile photoChristian Hudon's profile photo
extremely Bright Potential Future?  extra Badass Probe Functions?  entirely Beautiful Programmatic Flair?
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
#opticalexperiments Parisian style with +Valentin Rothberg and +Peter Senna Tschudin and real beer (i.e. Guinness or two...)
Jean-Michel Rubillon's profile photoIan Kumlien's profile photoSriram Ramkrishna (sri)'s profile photoPeter Senna Tschudin's profile photo
Beamish? come on now..
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
"docker" functionality implemented in 100 lines of bash, very nice hack.  Shows just how powerful btrfs is, along with the 'ip' tool.
bocker - Docker implemented in 100 lines of bash
Haikel Guemar's profile photoAnika Kehrer's profile photoKrzysztof Wilczynski's profile photoHoang Tran's profile photo
i shouldn't say this, but i love bash. 
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
New kernel release announcement, made from 30k feet, with Walter the Labradoodle sitting in the seat next to me and then falling asleep on my arm. ( )


Also, now that 4.1 is out, time to announce that it will be the next "Long Term Support" kernel I'll be maintaining for the next two years.
Cristiano Barbosa Rodrigues's profile photoAlessandro Di Giacomantonio's profile photoSheila Mihiko's profile photoCameron Wood's profile photo
LOL... that cute furry is really sitting in a plane, isn't it? ... and term "Kernel Watchdog" gains an absolutely new meaning :D
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
Three tiny Tux cases came in the mail. A bit big for "modern" board designs, but I'm sure I can get my beagle bone black to fit well inside them.
Jochen Schafft's profile photoAndrew Schott's profile photoCarla Sella's profile photoDjalal Harouni's profile photo
You can surely stuff your GL-Inet in them, and since it has WiFi and can be powered with almost nothing, you might manage to build a wireless ("tailless" ?) tux :-)
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
I got to see this recently, and it's amazing. Combine a great storyteller with amazing technology and good things happen.  It's now available for everyone to download. Watch it with headphones.
A day after leaving the "Fast and Furious" franchise, Justin Lin got a curious phone call. Lin, who had directed four of the street racing-themed action movies, was asked by Google to collaborate o...
Irshad Pananilath's profile photoLucas Santos's profile photoJani Nikula's profile photoJorge Nerín's profile photo
Yeah, sorry...Spotlight eligible devices.  I can't imagine why a Nexus 7 can't display these media, but OK.  I guess it's for me to wonder and Google developers to know, because these Play doohickeys never tell you why your devices aren't compatible with the app.  Guess it's not going to happen for me.

In skimming through the page for the links, it didn't look like there was a direct link to this short movie.
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
I see more and more projects doing the "curl | sudo bash" method of installing something.  Not good on huge number of levels.  This is a good rant of people doing this for containers.

Yes, I know docker doesn't support signed images yet, hopefully that will happen someday...
None of these "fancy" tools still builds by a traditional make command. Every tool has to come up with their own, incomptaible, and non-portable "method of the day" of building. And since nobody is still able to compile things from scratch, everybody just downloads precompiled binaries from ...
Michael Faille's profile photoA. David's profile photoJorge Nerín's profile photoJonas Kalderstam (Space Cowboy)'s profile photo
+Edward Morbius Unless you trust the server your sourcing from....  But nothing connected to the public Internet can be trusted.
Add a comment...

Greg Kroah-Hartman

Shared publicly  - 
Retro computing combined with music, great work.
Sven Sternberger's profile photoDiego Ruggeri's profile photoChiang Keeper's profile photoDjalal Harouni's profile photo
Fantastic! Makes me miss my ZX81, wish I still had it.
Add a comment...
  • Linux
Basic Information