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Category: plasma (Page 1 of 2)

My 2020 with KWin Wayland

Over the last few years and especially since the Wayland goal vote, the Plasma team, we have been focusing on having our Plasma Wayland experience work at least as good as our traditional Plasma X11 experience does. Today I’d like to wrap up my experience on this front for 2020.

Despite having been working on KDE and even Plasma projects for a long while, I’d never gotten much deep into working on KWin internally. I dipped my toes in it in 2019 when working on the key states feature (that plasmoid that says if caps lock is pressed or not, which we needed because the KDE Slimbook didn’t have an LED for the Caps Lock). Here I’ll discuss a bit how it evolved over time.

Features

Tablet support

It’s probably been my first big feature contribution to KWin. From 5.19 you’ve been able to use your tablets to draw things, all features should work fine and life should work. In the beginning, I was mostly interested in getting the 2-in-1 tablet with a pen work, hence implementing this one first.
The rest of the spec implementation is pending review here and hopefully should make it into 5.21: https://invent.kde.org/plasma/kwin/-/merge_requests/559

Screen casting support

This is something I’ve worked on mostly with my Blue Systems hat on, but still is something very important for our daily usage of Wayland, especially nowadays where working remotely is more important than ever and sharing our screens and windows is something that we need to do on a daily basis.

KWin used to support already sharing screens, or rather xdg-desktop-portal-kde could, now we centralised the implementation in KWin and made sure it’s as performant as possible. It was admittedly rather complex to put together, but allowed me to understand how the system works and helped me have a better insight of the architecture.

Input Methods

Plasma Mobile is becoming a palpable reality and input is very important on any touch device. In Plasma Mobile we’d been relying on having Qt’s embedded virtual keyboard since the beginning and while it worked reasonably well, we needed to make it possible for us to offer more and better solutions. This time, we implemented the unstable input-method protocol which allowed us to use keyboards implemented in a separate process, hence making it possible to integrate the Maliit keyboard transparent, as well as the weston keyboard if minimalism is your thing.

Maliit keyboard

This, of course, opens the possibility of much more development on top in terms of other better virtual keyboards, improving the current ones or the integration of more esoteric kinds of input methods (e.g. ibus, fcitx, emoji keyboard or even spell checkers and the likes).

Developing comfortably

Something that was clear to me as soon as the Wayland Goal was shaping up was that we had to find ways to free ourselves a bit from the ABI limitations. From the beginning, Wayland interfaces started to be developed in KWayland under KDE Frameworks 5. This meant that server-side implementations had to stay backwards compatible to certain versions of KF5 and that we couldn’t do certain things. We moved KWayland Server components into a separate component here, that is released with Plasma and we can develop as we see fit: https://invent.kde.org/plasma/kwayland-server/. Note that KWayland Client classes stay there where they always were.

This has allowed us in turn to adopt the usage of qtwaylandscanner, which is a tool that generates certain boilerplate C++ code for us from the xml spec, allowing us to focus on the parts we care about in the implementation. This makes Wayland protocol implementation a bit more straightforward while removing some code. You can see the MRs Adrien and Vlad made doing this if you’re curious about the changes it conveys. Our first protocol implementation to use qtwaylandscanner was the keystate protocol I mentioned earlier.

Talks

As it’s important to explain what we do so people are aware of it, I decided to take some time this year to explain the different aspects of our Wayland initiative and overall why Wayland makes sense. You can see it explained here, I wouldn’t recommend you to look at them all, but it could be useful for you to look at the one that fits your perspective better.

KWin and Wayland

Wayland for Product creators

Wayland for App Developers

Plasma Wayland: donde estamos y como ayudar (in Spanish)

Future

I know there’s a lot of really exciting stuff coming up from the team. If you’re interested, stay tuned. We will be having a sprint early January to discuss different topics from major roadblocks to a light and comfortable experience.

Consider joining us either at the sprint or at the Wayland goal forums and work with us towards a better experience using Free Software and Plasma.

Developing KDE as Products

One thing that is special about KDE software is how it can mean different things depending on your perspective. This is very powerful from a technical perspective, but can make our work harder when we want to convey what our piece of software does and how it will affect its users’ life. How do we optimize our product development towards user acquisition and support?

At Akademy, I discussed shedding some light on the blurry lines that sometimes define our products, and did so based around the Marketing-Mix I was taught at university (so no, I’m not an expert!). I presented it first at a talk, then we had a subsequent BoF session to discuss it and see how it mapped to some projects (we did Plasma and Okular, as a test) to get acquainted with the concept.

What will evolving this process look like? For starters, having some people more knowledgeable on the topic involved. Some already told me they are interested in helping. Big thanks 😊. And then, let’s get our hands dirty.

Maybe more hands-on for each product? I can see ourselves sitting down and discussing how the status quo contrasts with the picture the Marketing Mix would suggest for our products. I have done it for some, and I have the feeling that there is a lot of unexplored potential.

Is your work available on the places you would like it available? Is the product you have in mind the same you’re promoting?

Now are you interested in helping with this process? Would you like to see how we can polish the product you are maintaining? Is there a product in KDE that you think could use this kind of help? Comment down below or send me an e-mail at aleixpol@kde.org and I’ll see to finding some time to sit down and working on it.

Developing KWin Wayland

On the last few weeks I’ve been looking at KWin more closely than in the past. It’s definitely a special beast within KDE and I figured it could be useful to give some hints on how to develop and test it.

When developing something, first step is always to compile and get the code installed and usable. It’s especially delicate because when we mess up our system becomes quite unusable so it needs to be done with care. To prevent major damage, we can probably try installing it into a separate prefix (See this blog post, change kate for kwin).
Second step is to make sure that modifying the code will modify the behaviour you perceive. This is what we’ll focus on in this piece.

Bear in mind most of the things I’m saying here are possibly obvious and not news, but it’s still good to have it written in case you feel like building on this (not fun to come up with) experience.

Testing KWin, Nested

That’s the first that we’ll probably try. It’s simple: we run a kwin_wayland instance within our system, it shows a window with whatever we’re running inside. I find it useful to run a konsole inside to trigger other applications. It’s also possible to point processes run elsewhere to that socket too but I haven’t really come across the necessity.

We’ll run something like:
kwin_wayland --exit-with-session konsole

Or even:
kwin_wayland --exit-with-session "konsole -e kate"

In any case, a good old kwin_wayland --help. The --exit-with-session bit isn’t necessary but it makes it useful to easily close it.

One of the biggest advantages of using it like this is that it’s very easy to run through gdb (just prefix with gdb --args kwin_wayland...), so still something to remember.
This works, but it’s usefulness is limited because important parts won’t be run: input, which will come from the actual session rather than from the kernel; and drm, which will go into the virtual session than to the kernel for the same reason.

TL;DR: if you’re modifying KWin to talk to the kernel, this won’t work.

Testing KWin, standalone

Next thing to try is to run it separately. Now you’ll want to move to a tty (e.g. ctrl+alt+F2) and run the same command as earlier. Now we’ll run the same code as above. Instead of getting a window now we get it full screen and using DRM and libinput straight from the source. *yah!*

It’s still quite uncomfortable though: the output will be going to the tty which we can’t see because we have kwin on top and if it crashes we’re at a loss. Also running it with gdb is a pain because we can’t interact with it.

That’s why for this I’d recommend to ssh into the system from another one. I’ve found the sweet spot there to use a combination of ssh and tmux (screen should work as well, there’s tons of doc on how to use either online). Using ssh we find 2 main problems: if the connection breaks the whole set up is left in a weird situation and from ssh we don’t really access the tty.

If you don’t have 2 computers available, you can ssh from a phone as well, should be good enough, especially if you can get an external keyboard, although a nice screen is always useful.

So what we’ll do is:

  • Make sure our system has sshd running, check the IP
  • host$ tmux
  • othercomputer$ ssh $IP
  • othercomputer$ tmux a

And then we’re seeing the same on both, and we can run kwin_wayland on either and everything will work perfectly: we’ll see debugs we may be adding, we’ll get to kill it with Ctrl+C if we please, we can run gdb, add breakpoints. Anything. Full fun.

Problem being it’s just KWin and there’s more to life than a black screen with a dancing window.

Testing a full Plasma Session

To start Plasma Wayland from a tty we run startplasma-wayland. This gives us a complete Plasma instance on Wayland. The same as if we were running it from a display manager like SDDM. Running it from another system tmux still has advantages, like we’ll get to see the debug output. Starting a kwin_wayland session under gdb is way beyond this blog post and barely useful considering the standalone approach I mentioned earlier. What we can do though is to attach to the running gdb.

From the other system (on tmux or not, although I find it useful to just put it in another tab) we can run sudo gdb --pid `pidof kwin_wayland` and it will attach. Then you can add your gdb business: breakpoints, make it crash, look at backtraces, print variables or just stare at it hoping things get fixed automatically.

tmux with logs

Other

There’re other things that have proved useful to me like running it on valgrind or with a custom mesa build + modified LD_LIBRARY_PATHS. This works as with any other project, except it doesn’t by default.

KWin has a safety system set in place that prevents running it on emulators like valgrind and prevents LD_LIBRARY_PATHS from being tampered with. Which is great in general but prevents us to do certain things.

To address this in our build, we can comment out the code in kwin/CMakeLists.txt where ${SETCAP_EXECUTABLE} is called on kwin_wayland. You’ll need to make sure kwin_wayland is recreated, so remember to host$ rm bin/kwin_wayland. This bit here made me waste a fair amount of hours mind you, so it’s worth keeping in mind.

It’s also worth remembering there’s a ton of debugging tools that can be used. Here’s some:

  • WAYLAND_DEBUG=1 environment variable to see how the wayland protocols are flowing.
  • gpuvis, useful to get an idea of how rendering is performing.

Also note that all of this applies for Plasma Mobile as well, where it’s also useful for applications as well, where it’s most convenient since you get a proper keyboard and screen to look at debug output and gdb traces.

Hope this was any useful to you.

Happy hacking, stay safe!

Meet KDE in València

During the next days, we’ll be having several sprints in València.

First we’ll be having the KDE e.V. Board on Monday and Tuesday then we’ll be having two big sprints:

  • Plasma, where we’ll be planning and working on the features for the next year (or more!)
  • Usability & Productivity goal’s that will look into different applications and components in KDE that need attention to work properly and improve them.

If you are around and you’d like to meet the different groups, we’ll be having open dinners so you can join and ask us anything.

  • The Board dinner will be next Monday 17th June at 20:30.
  • The Plasma & Usability dinner will be next Saturday 22nd June at 20:30.

Send me an e-mail to aleixpol@kde.org saying when you’d like to come.
The location will be decided depending on the amount of people who ends up coming.

Last but not least, big thanks to Slimbook for hosting us for this sprint! 🙂

Reaching out

One of the activities that we have been promoting is joining conferences on topics that we’re interested in. Last September I joined two of them: the Libre Application Summit and EduCode.

Reaching out within the community

In the Linux community we’re portrayed as tribalistic quite often, there’s good reasons of that. Having been part of KDE day to day for years, I also must say that it’s clearly been blown out of proportion. There’s collaboration all over the place and we should celebrate when it happens. Sitting together and sharing visions is useful, which we did in the last Libre Application Summit in Denver.

Among others, we learned about Flatpak’s internals, elementary’s software distribution approach, fancy new ways of distributing linux operating systems and how some free software we have available on linux can be used by graphics designers and how they reach them. Of course, there were the KDE bits that Albert and I brought.

I would say that the ultimate goal for all this wasn’t exclusively to learn about it but to actually sit together and talk. Which we did and I’m looking forward to do so again next year, hopefully with the rest of communities working on desktop, applications and distribution.

Reaching out to users

It’s a completely different story, for sure, but it needs doing too. In this occasion we joined a conference full of Belgian and French teachers who are interested both in Free Software and having the best educational tools available for their students.

This is especially important for two main reasons: we get to explain to some of our most prominent stakeholders what our software does and why it’s great but also we get to see how they react and what they miss. Caring and listening to users is crucial to the health of any project.

I was tempted to upload another picture of the crew up there (Adriaan, Paul and myself) but it’s rather unflattering to say the least, so we’ll stick with Paul looking all smart. 🙂

Of course, these were only the conferences I attended the last few months, but there’s been several other conferences where KDE has joined, join the planet KDE to know more!

Tracking a QObject’s life

Why?

One of the interesting things about QML is that it leverages OOP property semantics of QObject to drive its declarative workflow.

How?

We attach into any QObject the developer requests and monitor it (and optionally all it’s children).

To gather the information we need, we will collect information for every property and connect to the property’s notification signal to see when it changes.

What?

This is the repository:https://phabricator.kde.org/source/kobjecttracking/.

This allows us to see:

  • Spurious property change notifications
  • Property changing bursts (i.e. same property changing values repeatedly in a short amount of time)
  • How a change in a value can have an effect on other properties

At the moment we have two ways of inspecting an application:
On one hand we have warnings that allow us know specific things and even add breakpoints to the sore points. The warnings at the moment look like this:
repeated value ScrollView_QMLTYPE_43(0x5648c6d97b50) width QVariant(double, 320) 8 times
repeated value Kirigami::BasicTheme(0x5648c6986ac0) backgroundColor QVariant(QColor, QColor(ARGB 1, 0.988235, 0.988235, 0.988235)) 11 times

Additionally, we have a timeline view output from tracking. You can see an example of plasmashell run here.

Future

An idea would be to integrate automatically ModelTest, so if a QAbstractItemModel is found, a ModelTest instance is attached that makes sure the model is true to its promises.

Another thing that bothers me is that we are forced to compile it into the application. If we could make it possible to have processes attached or start the application somewhat automatically (like GammaRay does, wink-wink) we would ease the adoption of these tools.

What do you think? Do you think it’s useful?
Feedback very welcome.

A laptop by KDE

Earlier this year we announced a joint venture between KDE and Slimbook that we named the KDE Slimbook.

Last Akademy we had the opportunity to meet the Slimbook team and discuss its purpose and future. I’m quite happy about the discussions, here’s my feedback.

KDE Slimbook

Why?

Before talking about future stuff, let’s set the context.

Personally, this has been a long-standing pet-peeve of mine. We create software solutions for virtual hardware specifications. We require our users to go the extra mile by replacing the manufacturer’s operating system, often with some annoyances because their hardware isn’t properly supported. This is not necessarily our fault, but most of us agree that we should improve this situation.

On the software side of things, while it’s our area of expertise, we are still far from being able to deliver the product we would like to give. Our ecosystem is still complex and our users have to take several decisions, some of dubious nature.

Hence, I started pushing for this project with some colleagues from KDE.

Where are we?

As discussed in the Akademy presentation, the project worked reasonably well. Devices were delivered and the KDE community does see value in the project.

We have reached a point where we understand the value of the initiative and understand the environment much better. We are happy with the results so far and we see room for improvement; both in the task we do to make a better device as well as in defining the product.

Future

I want to see the project moving forward and I will keep working towards better cohesion between hardware vendors and KDE. In the future, I would like to see the devices that we see available, especially when it comes to different use cases, and therefore form factors.

I don’t think it makes sense that we continue doing it just to do so. There is a good deal of hardware vendors that will offer devices with good setups. Most of them they will even offer you these laptops with KDE on them upon demand. If we put our effort in such projects, it needs to be because we are making something special.

Let’s not get ahead of ourselves. One step at a time. Let’s continue to provide good solutions by staying simple by default but powerful when needed.

Getting Free Software into our users’ hands

In KDE we cover a mix of platforms and form factors that make our technology very powerful. But how to reach so many different systems while maintaining high quality on all of them?

What variables are we talking about?

Form factors

We use different form factors nowadays, daily. When moving, we need to be straight-forward; when focusing we want all functionality.

Together with QtQuick Controls, Kirigami offers ways for us to be flexible both in input types and screen sizes.

Platforms

We are not constantly on the same device, diversity is part of our lives. Recommending our peers the tools we make should always be a possibility, without forcing them into major workflow changes (like changing OS, yes).

Qt has been our tool of choice for years and it’s proven to keep up with the latest industry changes, embracing mobile, and adapting to massively different form factors and operating systems. This integration includes some integration in their look and feel, which is very important to many of us.

Devices & Quality Assurance

We are targeting different devices, we need to allow developers to test and make it easy to reproduce and make the most out of the testing we get, learn from our users.

Whatever is native to the platform. APK (and possibly even Google Play) on Android, Installers on Windows and distribution packages for GNU/Linux.
Furthermore, we’ve been embracing new technologies on GNU/Linux systems that can help a lot in this front including Snap/Flatpak/AppImage, which could help streamline this process as well.

What needs to happen?

Some of these technologies are slowly blooming as they get widely adopted, and our community needs as well to lead in offering tooling and solutions to make all of this viable.

  • We need straightforward quality assurance. We should ensure the conditions under which we develop and test are our users’ platforms. When facing an error, being able to reproduce and test is fundamental.
  • We should allow for swift release cycles. Users should always be on fresh stable releases. When a patch release is submitted, we should test it and then have it available to the users. Nowadays, some users are not benefiting from most stable releases and that’s makes lots of our work in vain.
  • Feedback makes us grow. We need to understand how our applications are being used, if we want to solve the actual problems users are having.

All of this won’t happen automatically. We need people who wants to get their hands dirty and help build the infrastructure to make it happen.

There’s different skills that you can put in practice here: ranging from DevOps, helping to offer fresh quality recipes for your platform of choice, improving testing infrastructure, or actual system development on our development tools and of course any of the upstream projects we use.

Hop on! Help KDE put Free Software on every device!

Discover more in 2017

With 2017 starting, we’re getting ready for the next Plasma 5.9 release and with it a new Discover release.

This will be a special release for two main reasons: further add-ons integration and Kirigami.

New Stuff

One thing pending for a long time was to actually better integrate the different parts of the system that can be integrated. To do so, Discover now will automatically import all knsrc files present on the system and offer them as categories.
We’ll be able to go beyond Plasmoids and Comics (!) and make it possible to explore: Plasma Look and Feel themes, cursors, icon themes, window manager add-ons and different application-specific resources.

This won’t have a big impact on Discover’s performance because the backend code was refactored to be able to have several backends loaded even without knowing all of the resources available. Queries are now asynchronous and parallel.

Discover KNS Addons

Kirigami

Kirigami was adopted in the previous release already, and this release will use Kirigami 2, the port to which did not require much work.

The most significant improvement is the inclusion of keyboard navigation, which was requested by several people and is now finally available. Do you hate it when you’re required to use the mouse? Rejoice!

Extra: Snappy support

It’s 2017, not all of the applications are coming from your distribution anymore. To start getting things in place for different software distribution sources I started working on a Snap backend, which allows us to manage applications coming from this system.
Some work will still be required and it won’t be included by default, since it doesn’t yet support AppStream (although we discussed it and it seems it will happen soon), but if you’re curious feel free to take a look and give your feedback!

GNU/Linux bundled application ramblings

It’s impressive how in the last few months (and especially the last few weeks) the discussion around bundled applications for the GNU/Linux Desktop has sparked.

It’s especially interesting because:

  • The problem is not new.
  • The solutions that have attempted to tackle the problem in the past have been ignored (both by us developers and by distributions).

The TLDR

First, let me try to subjectively summarize the problem: Historically, the resources we get in GNU/Linux come from the distributions. Anything: executables, libraries, icons, wallpapers, etc. There’s been alternatives to all of those, but none has flourished as a globally adopted solution.

This guarantees that everyone using a distribution will have access to the resources the distribution can offer. The more powerful the distribution is, the more we get. There’s limitations nevertheless, so some restrictions have to get in place. The ensemble of limitations and technologies adopted will effectively define the user’s experience.

This works. It has worked for years and, given the technology is in place, it could easily keep working. Like in most engineering solutions there’s drawbacks and properly addressing them can bear some goodness. It seems like now it’s the moment to review this situation. Let’s enumerate some of the problems we have nowadays:

  • We have users using really old versions of our software with issues we’ve solved in versions they can’t use.
  • It’s really hard for GNU/Linux users to get users to test unstable versions of our software.
  • We have users who want to use fresh versions of some software but not in the whole system.

There’s been many solutions to fix those, some easily come to mind: ArchLinux’s AUR (with yaourt), Ubuntu’s PPAs, big-tar application packages, OpenSuse’s OBS, and possibly others.

Far from showing the maturity of the Linux desktop, what this depicts is the deep fragmentation we’re into: we have come up with different solutions that break the established distribution paradigm by lowering the restrictions and considering the resources offered as unsupported (often tainting the whole system).

What has appeared recently is sandboxing. It’s especially interesting because by letting the users execute any binaries we’re increasing the exposition of their systems. Hence, jumping from our distributions’ nest into the lions. As always, sandboxing creates new challenges: It requires changes in applications (or frameworks) to adapt, often creating a user interaction fence (e.g. a popup asking if you let Kamoso access the webcam). For what it’s worth, that’s not new: Android does it, OS X does it, Windows does it (from the Store), Chrome OS does it, etc.

Now where are we?

We need to decide about GNU/Linux’s future. Or at least, we need to understand what Plasma users will have available. So far, most of the noise comes from the big players in the business trying to differentiate their products, meaning incompatible versions.

Without an agreed unified solution, we’ll have to assume we’ll end up having installed snappies, flatpaks, AppImages as well as applications from the distribution. Then it’s just a matter of:

  • Presenting it properly so that the user knows the risks taken by executing an application (!)
  • Make sure we don’t lose many features by sandboxing.

Still, one of the good things of this new approach is that it shouldn’t have to be necessary to have several people dedicated to build every single application and component. If the solution is to add 3 more solutions that will need dedicated people, we’re not really moving forward.

Building

As soon as we’ve decided how we want to work, then the interesting stuff needs to appear. If this is properly engineered, it can bring really interesting possibilities that now we hardly ever find:

  • Newer versions of applications on administered systems (e.g. universities).
  • Enabling stable distributions on professional environments.
  • Beta channels.
  • Binary application 3rd party extensions.
  • Provision of debug symbols (some distros don’t offer them).

To finish the fantastic post, a note for the dreamers:
How easier would all that be in a microkernel architecture?

We need you!

Of course this will be a long journey and we need your collaboration. This year in Randa we started working on all these problems in several different angles. It’s important for the KDE Community to have your support, so we can keep providing quality software. Consider donating, doesn’t need to be a lot, everything counts.

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