flatpak: cannot add flathub repo on kubuntu 20.04 LTS: TLS support is not available

error: Can't load uri https://flathub.org/repo/flathub.flatpakrepo: TLS support is not available
 

Fix: need to set env. var:

 GIO_MODULE_DIR=/usr/lib/x86_64-linux-gnu/gio/modules/ flatpak -v remote-add --if-not-exists flathub
https://flathub.org/repo/flathub.flatpakrepo

Thinkbook 13s ITL G2 headphones hissing sound, noise fix

Kubuntu 20.04 LTS

Problem: wired headphones reproduce constant hissing sound, noise changes with the cursor movement etc.

Solution:

 sudo hda-verb /dev/snd/hwC0D0 0x1d SET_PIN_WIDGET_CONTROL 0x0

 

Sources:

https://www.reddit.com/r/thinkpad/comments/8j8208/audio_crackling_through_both_headphone_jack_and/

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1805079/comments/20

 

xubuntu 18.04 mouse sensitivity fix

If GUI mouse sensitivity settings don't work try using commands:

> xinput

 Will output:

Virtual core pointer                        id=2    [master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer                  id=4    [slave  pointer  (2)]
⎜   ↳ Logitech USB Receiver                       id=9    [slave  pointer  (2)]
⎜   ↳ Logitech USB Receiver Consumer Control      id=10    [slave  pointer  (2)]
⎜   ↳ Logitech USB Laser Mouse                    id=15    [slave  pointer  (2)]

Remember those id's or use "Logitech USB Receiver" and "Logitech USB Laser Mouse" device names in the following commands.

> xinput list-props 'Logitech USB Laser Mouse'

Device 'Logitech USB Laser Mouse':
    Device Enabled (155):    1
    Coordinate Transformation Matrix (157):    1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
    libinput Natural Scrolling Enabled (289):    0
    libinput Natural Scrolling Enabled Default (290):    0
    libinput Scroll Methods Available (291):    0, 0, 1
    libinput Scroll Method Enabled (292):    0, 0, 0
    libinput Scroll Method Enabled Default (293):    0, 0, 0
    libinput Button Scrolling Button (294):    2
    libinput Button Scrolling Button Default (295):    2
    libinput Middle Emulation Enabled (296):    0
    libinput Middle Emulation Enabled Default (297):    0
    libinput Accel Speed (298):    1.000000
    libinput Accel Speed Default (299):    0.000000
    libinput Accel Profiles Available (300):    1, 1
    libinput Accel Profile Enabled (301):    1, 0
    libinput Accel Profile Enabled Default (302):    1, 0
    libinput Left Handed Enabled (303):    0
    libinput Left Handed Enabled Default (304):    0
    libinput Send Events Modes Available (274):    1, 0
    libinput Send Events Mode Enabled (275):    0, 0
    libinput Send Events Mode Enabled Default (276):    0, 0
    Device Node (277):    "/dev/input/event11"
    Device Product ID (278):    1133, 49257
    libinput Drag Lock Buttons (305):   
    libinput Horizontal Scroll Enabled (306):    1

We need to set 'libinput Accel Speed' property to 1.0 value for maximum speed.

> xinput set-prop 'Logitech USB Laser Mouse' 'libinput Accel Speed' 1.0

Make a bash script and add it to "Session and Startup":

#!/bin/bash
#xinput set-prop 15 298 1.0
#xinput set-prop 9 298 1.0

xinput set-prop 'Logitech USB Laser Mouse' 'libinput Accel Speed' 1.0
xinput set-prop 'Logitech USB Receiver' 'libinput Accel Speed' 1.0

ubuntu avahi fix for Belarus/Beltelecom/Byfly

If there's "Avahi Service discovery disabled" popup displayed, check
"host -t SOA local".
If there's something like "local has SOA record local. root.mgts.by", you can make avahi ignore that wrong configuration via editing /etc/default/avahi-daemon:

AVAHI_DAEMON_DETECT_LOCAL=0 

xubuntu 18.04 installing with nvidia graphics, tearing fixes

Before installing (running LiveCD/USB)

Edit GRUB options in the live-cd menu by adding "nomodeset" argument to the  kernel parameters string.

After installing

Repeat "nomodeset" option as described above before the first boot.

1. "apt install nvidia-driver-435"
2. Reboot
3. In "NVidia X Server Settings -> X Server Display Configuration -> Advanced..." switch on "Force Composition Pipeline".
4. Enable XFCE compositor (Menu->Window Manager Tweaks->Compositor->Enable display compositing)
5. Enable the "Synchronize drawing to the vertical blank" option in the "Window Manager Tweaks" "Compositor" tab.

lubuntu 16.04 experience, amd radeon integrated video hdmi sound problem

Lubuntu 16.04 on

GA-E2100N (rev. 1.0) | Motherboard - GIGABYTE 

AMD® E1-2100 dual-core APU with Radeon™ HD 8210 graphics SoC

- quick to boot, a bit over 200 MB RAM occupied when all is loaded.
- 3D acceleration works out of the box
- no HDMI sound, fixed by installing pulseaudio
- no video playback acceleration -- fixed by installing vdpau-mesa drivers and setting vdpau in the mplayer as output device.

Linux on GA-E2100N (AMD E1-2100 APU)

Linux experience on GA-E2100N (rev. 1.0) with AMD E1-2100 SoC.

Xubuntu 14.10.

Hardware:

Gigabyte GA-E2100N (rev. 1.0) board

CHIEFTEC IX-01B-90W mini-ITX case with 90W power supply.

GeIL PC10600 4GB CL9-9-9 D3-1333 (GN34GB1333C9S)

Kingston V300 120GB

HDMI cable

HD-ready TV (1360x768)

Logitech K400r wireless keyboard with touchpad

TP-Link TL-WN722N USB wifi adapter

BIOS options to note:

Fast Boot: Disabled (when left Fast and Ultra fast the board does not respond on reboot and required BIOS CMOS clear jumper to be set to restore normal operation)

Secure boot: disabled

Enabled EFI only in all options (disabled all legacy stuff).

On-board COM, LPT, LAN, Audio codec: disabled.

OS, minimal settings:

Xubuntu 14.10, installation USB stick in EFI mode. 

Launched live, started 

GParted and created EFI boot partition (200MiB), system (25GiB), swap (512MiB) and storage partitions, left ~8GiB unallocated for SSD overprovisioning.

Launched installation, selected all partitions as created by GParted ("something else" menu option).

After reboot disabled Light-locker, Compositor, installed Synaptic, made sure mesa-vdpau drivers installed, installed mpv for video playback, modified /etc/fstab to contain "discard,relatime" options for root and storage partitions to optimize for SSD.

"~/.mpv/config" contains:

hwdec=vdpau 

This line makes mpv use 5-10% CPU for 720p x264 videos, 60-100% otherwise.

Edited line in the "/etc/pulse/default.pa" to contain:

load-module module-udev-detect tsched=0

(added "tsched=0" argument to fix sound over HDMI issue (crackles, stutter).

Kodi (XBMC)

Enabled VDPAU acceleration only. Still uses too much CPU (~30-50% per core), without VDPAU uses 100%.

Problems

Heavy CPU usage in Kodi/XBMC.

Proprietary Catalyst drivers give poor performance for video playback, better stay with default Gallium3D.

No hardware acceleration for youtube, HTML5 videos, flash, although firefox is quite responsive.

Success

Low CPU usage with VDPAU in "mpv", very fast seeking times in any video file, no problems in playback.

Sauerbraten/cube is fast to start and very responsive, playable at 30 FPS with all effects at 1360x768 fullscreen.

Summary:

Max 71 C Core temparature at constant CPU load, 65 C at idle (neither fans in the case, nor CPU fan used, absolutely silent passive-cooled system), BIOS shows 55C CPU and 40C motherboard temperature values, touched the heatsink, and can confirm -- it is just warm, not burning. 

Quite responsive system with good multithreading (2 cores), although takes a lot of time to compile C/C++ code.

All the hardware automatically detected and worked out of the box, small tweaks required. Perfect hardware for a Linux installation.

Genius G-Pen 560 on Xubuntu 14.10 via Aiptek driver

install xorg-server-aiptek driver.

create a settings file:

sudo vim /usr/share/X11/xorg.conf.d/70-aiptekmy.conf

Section "InputClass"                                                           
    Identifier "pen"                                                           
    MatchProduct "Aiptek|AIPTEK|aiptek"                                        
    MatchDevicePath "/dev/input/event*"                                        
    Driver "aiptek"                                                            
    Option "SendCoreEvents" "true"                                             
    Option "USB" "on"                                                          
    Option "Type" "stylus"                                                     
    Option "Mode" "absolute"                                                   
    Option "zMin" "0"                                                          
    Option "zMax" "1023"                                                       
EndSection

Genius G-Pen 560 under Debian 7.6

Download https://launchpad.net/wizardpen sources.
in the README file there are instructions to install dependencies.
Do ./configure, sudo make install.

edit /usr/share/X11/xorg.conf.d/70-wizardpen.conf

Section "InputClass"
   Identifier "wizardpen"
   MatchIsTablet "on"
   MatchDevicePath "/dev/input/event*"
   MatchTag "wizardpen"
   Driver "wizardpen"
   Option               "TopX"          "185"
   Option               "TopY"          "372"
   Option               "BottomX"       "11811"
   Option               "BottomY"       "8793"
   Option               "TopZ"          "32"
EndSection

Restart and enjoy!

Thinkpad x220

Bought Lenovo Thinkpad x220 (with core i5, tn-film display, no ips configurations where available for less than $2000), installed xubuntu. Everything works out of the box, had to tune hdd power management: hdparm -B 254 /dev/sda to extend hdd's live. Also installed hdapsd for active shock protection and tp-smapi-dkms. Really good device for work and hobby.

Lazarus problem solution for Ubuntu 11.10

" Lazarus applications have problems to run on latest Ubuntu 11.10 where the reason is new Taskbar menu and scrollbar.

To get application running like on older Ubuntu we have to remove some functionality from Ubuntu using by this command:

sudo apt-get remove appmenu-gtk3 appmenu-gtk appmenu-qt
liboverlay-scrollbar-0.2-0 "

http://62.166.198.202/view.php?id=20520

FreePascal experience

Tried FPC 2.4.4 recently, what I must say, Lazarus and console fpide are unusable under Ubuntu 11.10 and MacOSX -- crash all the time, no debugger support and strange GUI bugs, although I have not tried them under Windows.

However, the big POSITIVE side is that the compiler (FPC) is a lightning fast one and easy to install at any platform. It's even faster than javac. I'm really impressed. And GDB understands well pascal programs, tried to debug and it's amazingly feature rich. The language is plain simple and you can easily program in any decent text editor. I really enjoyed playing around with it. The generated applications are lightweight like in good old times, native, fast, not so hungry for memory and cpu resources. Also FPCMAKE is a good tool if you plan to develop a more or less complex application.

FPDOC tool is not what I like to use (it requires documentation not in the source comments but in a separate xml file), better to pick pasdoc (http://pasdoc.sipsolutions.net/) for those who used to javadoc and doxygen.


As for the Pascal programs I've used -- they are not pretty stable, I think it's the fault of the poor memory management strategy applied. It's better to use reference-counting techniques like in GNUstep/Cocoa than TComponent's sole ownership and dangling pointers.

Playing with the compiler I have tried to implement a base class to do that counting and one more to track weak references. It was a success, so it's not the language fault but the programmers who use it, because my solution looks good and I plan to publish a library on GitHub if I ever program in FP.

One more deficiency is the lack of Unicode strings support in OS calls, e.g. for file names on Windows. Although it's no problem under Linux and/or MacOSX.

Generally FPC is a great tool, and there are a lot of useful libraries to make life easy.

jEdit performance workaround

Runs slow on my Ubuntu, but if I make

jEdit global options -> Appearance -> Show the systray icon to OFF.

it runs as fast as native. Strange bug on Gnome 3.

LDC under ubuntu 11.10 one more try

Installed through apt llvm-2.9, downloaded trunk LDC, executed ccmake, and added -ldl to LIBCONFIG_LDFLAGS. Successfully built!

Build tango, and adjusted /usr/local/etc/ldc.conf:

// This configuration file uses libconfig.
// See http://www.hyperrealm.com/libconfig/ for syntax details.

// Special macros:
// %%ldcbinarypath%%
//  - is replaced with the path to the directory holding the ldc executable

// The default group is required
default:
{
    // 'switches' holds array of string that are appends to the command line
    // arguments before they are parsed.
    switches = [
        "-I/usr/local/include/d",
        "-I/usr/local/include/d/tango/core/vendor",
        "-L-L/usr/local/lib",
        "-L-ltango-ldc",
        "-d-version=Tango",
        "-defaultlib=tango-ldc",
        "-debuglib=tango-ldc"
    ];
};

Ubuntu 9.04 on HP Compaq 6510b

Core2Duo T7250, 2GB, intel 965

LiveCD runs fine, all hardware works.
After installation everything works just fine except compiz -- it doesn't run, although 3D games like TuxRacer, Chromium etc. run smooth.