“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.

Continue reading “Help! No Volume Mute under Plasma 5!”

A clarification about (Linux) Mesa / Nouveau Drivers

Two of the subjects which I like to blog about, are direct-rendering and Linux graphics drivers.

Well in This Earlier Posting, I had essentially written, that on the Debian 9 , Debian /Stretch computer I name ‘Plato’, I have the ‘Mesa’ Drivers installed, and that therefore, that computer cannot benefit from OpenCL, massively-parallel GPU-computing.

What may confuse some readers about this is the fact that elsewhere on the Internet, there is speak about ‘Nouveau’ Drivers, but less so about Mesa Drivers.

‘Mesa’, which I referred to, is a Debian set of meta-packages, that is all open-source. It installs several drivers, and selects the drivers based on which graphics hardware we may have. But, because ‘Plato’ does in fact have an nVidia graphics card, the Mesa package automatically selects the Nouveau drivers, which is one of the drivers it contains. Hence, when I wrote about using the Mesa Drivers, I was in fact writing about the Nouveau Drivers.

One of the reasons I have to keep using these Nouveau Drivers, is the fact that presently, ‘Plato’ is extremely stable. There would be some performance-improvements if I was to switch to the proprietary drivers, but making the transition can be a nightmare. It involves black-lists, etc..

Another reason for me to keep using the Nouveau Drivers, is the fact that unlike how it was years ago, today, those drivers support real OpenGL 3, hardware-rendering. Therefore, I’m already getting partial benefit from the hardware-rendering which the graphics card has, while using the open-source driver.

The only two things which I do not get, is OpenCL or CUDA computing capabilities, as Nouveau does not support that. Therefore, anything which I write about that subject, will have to remain theoretical for now.

I suppose that on my laptop ‘Klystron’, because I have the AMD chip-set more-correctly installed, I could be using OpenCL…

Also, ‘Plato’ is not fully a ‘Kanotix’ system. When I installed ‘Plato’, I borrowed a core system from Kanotix, before Kanotix was ready for Debian / Stretch. This means that certain features which Kanotix would normally have, which make it easier to switch between graphics drivers, are not installed on ‘Plato’. And that really makes the idea daunting, to try to switch…



How NOT to control our Gaming Keyboards, from a Linux computer.

One of the commodities which serious computer enthusiasts might want to buy, is a gaming keyboard. One reason may be the fact that by coincidence, gaming keyboards tend to be sound mechanical keyboards as well, which have per-key switches, which in turn have the desired tactile response, which bubble-keyboards today often lack.

But then, one of the features which gaming keyboards may add, is the ability to store and play back macros when in gaming-mode, those macros being key-sequences which a player needs to enter repeatedly, but tires of typing each time.

Another feature gaming keyboards can have, is fancy LED back-lights, which can even be customized to highlight different groups of keys, depending on how those groups of keys are important to certain uses of the KB. ( :1 )

I just bought the “ThermalTake eSports Poseidon Z RGB”, with Blue Key-Switches. The blue key-switches are switches that not only give good tactile feedback, but also make a distinct, high-pitched clicking sound, at exactly the right instant, during a key-press.

They have mechanical hysteresis.

One less-optimistic side-effect for this, under Linux, is the fact that some of the customization of this KB requires that proprietary software be used, of which there only exists the Windows version. The main functioning of the KB will work under Linux (Debian / Stretch), but if we want to program the layout-coloring / highlighting, then we need to use the proprietary software. These layouts can then be stored in 1 out of 5 Profiles, on the KB itself, which has its own 32-bit embedded micro-controller (i.e., this KB has its own CPU).

I tried to find out, whether I could install the software under a specific Wine folder, and then create symlinks to various device-files that exist natively under Linux, so that those device-files will appear as generic, DOS-type serial ports. Since Wine, by default, does not have direct access to the host machine’s USB-connected hardware.

The result was, that I bricked the keyboard. I needed some support from the retailer who sold me the keyboard, to recover a fully-functional instance.

The sum total of what this means, is that I can use this KB under Linux. I must just store its customizations using an old Windows laptop I have – a dual-boot ‘Acer Aspire 5020′ – after which I can disconnect the KB from that laptop, and connect it to my main (Linux) desktop again.

(Edit 04/05/2018 : )


(One problem with trying to photograph this keyboard with a simple phone-cam is, the fact that the LEDs produce light with high intensity. This light tends to saturate the light-sensor in a conventional camera-phone, which in turn results in a reduction, to the recorded color saturation. I.e., when the BG light-level is normalized by a camera-phone, the brightest primary colors are off-the-scale, but limited to scale as encoded.

Therefore, Blues will seem to look similar to Greens, and Yellows look similar to Whites.

When seen with the naked eye, all these colors look very deep. )


Continue reading How NOT to control our Gaming Keyboards, from a Linux computer.

Installing a “Wacom” graphics / digitizer tablet under Linux.

I’ve just received my “Wacom Intuos PT S 2″ digitizer tablet – aka graphics tablet – which I had specifically bought, because there is some support for the Wacom series of tablets under Linux. I was able to get it working 100%, and also did get the ‘wireless kit’ to work, that I had ordered with it.

Under Linux, we need to have at least these two packages installed, in order to get this hardware to work:

  • ‘xserver-xorg-input-wacom’
  • ‘libwacom2′

If available, the following should also be installed:

  • ‘libwacom-bin’

Additionally I should mention that I did this on the Debian / Stretch computer I name ‘Plato’, on which I have Plasma 5 as my desktop manager. Although Debian and Linux do support Wacom, apparently, Plasma 5 as such does not. This effectively means that individual applications may have tablet-support, but that We’re not given a graphical module for the System Settings panel, from which to customize our tablet. For that reason, I needed to write a shell-script which does this for me:



xsetwacom --set "Wacom Intuos PT S 2 Finger touch" Touch off
xsetwacom --set "Wacom Intuos PT S 2 Pen stylus" Button 2 key "shift"
xsetwacom --set "Wacom Intuos PT S 2 Pen stylus" Button 3 key "ctrl"

xsetwacom --set "Wacom Intuos PT S 2 Pad pad" Button 1 key "button +3"
xsetwacom --set "Wacom Intuos PT S 2 Pad pad" Button 3 key "del"

xsetwacom --set "Wacom Intuos PT S 2 Pad pad" Button 8 key "ctrl" "c"
xsetwacom --set "Wacom Intuos PT S 2 Pad pad" Button 9 key "ctrl" "v"

xsetwacom --set "Wacom Intuos PT S 2 (WL) Finger touch" Touch off
xsetwacom --set "Wacom Intuos PT S 2 (WL) Pen stylus" Button 2 key "shift"
xsetwacom --set "Wacom Intuos PT S 2 (WL) Pen stylus" Button 3 key "ctrl"

xsetwacom --set "Wacom Intuos PT S 2 (WL) Pad pad" Button 1 key "button +3"
xsetwacom --set "Wacom Intuos PT S 2 (WL) Pad pad" Button 3 key "del"

xsetwacom --set "Wacom Intuos PT S 2 (WL) Pad pad" Button 8 key "ctrl" "c"
xsetwacom --set "Wacom Intuos PT S 2 (WL) Pad pad" Button 9 key "ctrl" "v"


Presumably, any other users with Plasma 5 desktop-managers will need to write similar scripts. Simply typing in the command ‘xsetwacom’ without any arguments, will display its basic usage.

It should also be noted, that after an X-server module has been installed, that will act as the input driver, at the very least, the X-server also needs to be restarted, before that driver will be loaded.

(Updated 03/24/2018 : )

Continue reading Installing a “Wacom” graphics / digitizer tablet under Linux.