“Help! No Volume Mute under Plasma 5!”

One of the subjects I blog about, is a computer I named ‘Plato’, which is running Debian / Stretch (Debian 9), and the desktop manager of which is Plasma 5, which is the successor to KDE 4.x .

One of the features which KDE 4 definitely had, was an icon in the notification-tray, from which we could control our volume levels easily, as well as to mute the sound temporarily, eventually to be unmuted again, at which point the earlier, unmuted settings should be remembered. At first glance it would seem that Plasma 5 has done away with this capability. Trying to solve this can cause people to spend hours searching the Internet, changing their Plasma 5 preferences, and maybe even forgetting their Plasma 5 preferences, because they disabled all their System Sounds from there.

Recently, I was on a fact-finding mission about this, and am willing to share my solutions.

Under Plasma 5, we really only need to have 2 packages installed, in order to control our volume-levels, etc., assuming that we have gotten our hardware recognized first. Those packages would be:

  1. ‘plasma-pa’
  2. ‘pavucontrol’

The first of these packages integrates with Plasma, and is also responsible for the icon in the notification tray. The second package gives us more control, over our sound-levels specifically, since Plasma 5 uses the Pulse Audio sound-server by default.

If we can see the icon in the notification tray, then a detail which we may overlook after we left-click on that icon, is a tiny little loudspeaker-symbol, on the left end of one of the volume sliders:


Left-clicking on this little symbol will cause the volume-bar to the right of it to become slightly pale, which will mean, that the device in question has been muted. I’m saying that ‘we’ could overlook that we even have this feature, because earlier, ‘I’ did not know that I have this feature.

But, this is only what the ‘plasma-pa’ package can show us. The ‘pavucontrol’ package gives us the ability to fine-tune our sound-levels as shown below:


Now, there’s an aspect to how this setup now works, which is slightly more complicated than how KDE 4 used to handle it. The Pulse Audio server attempts to adjust playback as well as recording levels, on a per-application basis. Thus, the view above is almost empty, because there were no applications playing back any sounds, at the moment I recorded this screen-shot.

A frustrating fact which can exist with this, is that some applications will only play a sound for 2 seconds, during which an additional volume-bar appears in the GUI, and after which that volume-bar disappears again, even if we did not have enough time to adjust one volume level. This happens to result from the design-decision, that volume-control should exist at the per-application level. Hence, even if we use media-control keys on our keyboard, those keys will only affect the one main application which happens to be playing, at any given moment. They won’t affect System Sounds.

But this description might sound like I have to say, ‘There is no problem,’ when in fact, under Debian / Stretch, There Is a problem. That problem, as I see it, lies in the fact that by default, the one volume-bar which the GUI has shown above, for all System Sounds, may not even work.

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Getting the Orca Screen-Reader to work under Plasma 5

In case some readers might not know, even though computing is heavily visual, certain advanced desktop-managers can be set up for impaired people to use – which also falls under the category of “Accessibility”. This includes the ability of the computer to speak a robotic description of what’s happening on the screen, in case a user can hear, but not see properly.

There are some users who feel they should stick with Windows, because Accessibility can be so hard to set up under Linux.

There are other users who are sorry they every clicked on “Accessibility”, because now they cannot turn it off.

If a visually-impaired user wants Accessibility set up on a Linux computer, I’d definitely suggest letting a trusted other person set it up, because until it’s set up, complicated things may need to be done, and accessibility will not be set up, so that the end-user will not benefit from Accessibility, while trying to set it up.

Some regular users find screen-readers trying for their patience, because of the fast, robotic voice, until they manage to shut it down again. Personally, I only find screen-readers trying, If I happen to have set one up late at night, because the voice could cause some sort of noise-complaint from my neighbors, droning on until I manage to disable it again. In the middle of the day, I don’t find these experiments trying.

I guess that a good question which some people might ask me, would be why I even do such an experiment, given that I’m not visually impaired and don’t need it. And what I do is set everything up until it works, and then disable it again.

On my recently-installed Debian / Stretch computer named ‘Plato’, which is also running Plasma 5 as its desktop-manager, I just did manage to get this feature to work, and then to disable it again.

(Updated 15h50, 1/17/2018 : )

The first thing I had to do, was install a long list of packages. The list below includes what was installed, but it should not really be necessary to give the command to the package-manager manually, to install everything here, because some of these packages will follow as dependencies from other packages. But here is a roundabout list:

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Getting Some Software To Run On My Linux Tablet, which Was Not Meant To Run

One of the computing adventures which I’ve been blogging about, is that I’ve been able to install a Linux Guest System, under the Android Host System, on my Samsung Galaxy Tab S, First-Generation tablet. I use the two Android apps, ‘GNURoot’ and ‘XSDL’, which can be obtained from Google Play, and which do not require root.

In this posting, I had as a message to my readers, that certain types of Linux applications are poor candidates for this sort of environment – a chroot-Linux-Shell, that connects externally to an X-server, which in turn seems to provide pure X-server protocol as well as a port, to connect PulseAudio clients to.

But in the same posting, I had named a specific Linux-application, which would solve each of the two purposes, and which in my opinion at the time, might have the best chances to run – assuming that any have a chance to run:

  1. ‘mhWaveEdit’
  2. LiVES

As some of my readers might expect, since that posting, I have nevertheless pressed ahead, and experimented with installing each of these Linux-applications, on the guest-system.

Long story short, I found that mhWaveEdit seems to work fine, and installed effortlessly, while LiVES does not.


One observation which I’ve made, is that the PulseAudio server built-in to the Android app ‘XSDL’, offers sound output, but not sound input. Hence, I cannot connect to the mike, which is built-in to the tablet. But this is a very minor issue, since I’ve exceeded typical usage-scenarios in what I’ve already been able to do.

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The Sort Of Software that will Not Run, on my Linux Tablet

In this posting I wrote, that I had installed Linux in a chroot-environment, on my old Samsung Galaxy Tab S, First Generation tablet, which remains an Android-based tablet. I did this specifically using the apps from the Google play store, named ‘GNURoot’ and ‘XSDL’, which do not require root.

Here, I gave a compendium of Linux-applications which do run in the resulting Linux guest-system.

I think that I need to point out a broad category of Linux applications that will always remain poor choices:

  • Audio Editors,
  • Video Editors.

The problem with any Audio Editor, is that it will eventually need to input and output Audio – not just edit sound files – and any Video Editor, needs to give a preview of all its video-clips – not just edit video files. This seems like a silly thing to write, but is non-trivial in my present context.

I have taken a Linux engine – GNURoot – and connected it to an externally-supplied X-server emulation – XSDL. The pipeline between these two Android apps is very narrow. It consists of X-server protocol – which is excellent and rendering text and GUIs, of shared memory at its maximum, and of a PulseAudio server, visible on the Linux side as such, but collectively running on the Android side as an SDL client.

I have no way to provide OpenGL or SDL on the Linux-side. What this means, is that virtually any non-linear video editor will want to see both installed on the Linux side, while neither is provided.

Continue reading The Sort Of Software that will Not Run, on my Linux Tablet