Thursday, June 14, 2018

Screen tearing in Ubuntu with xfce4 using intel HD4000 graphics

Recently I switched back from Unity desktop environment to xfce4 and I noticed a screen tearing when watching movies and even slightly when scrolling through websites. Needless to say, it is quite annoying and it should not be happening.

My laptop has a decent Intel core i5 CPU with Intel HD4000 graphics, which should be more than capable of playing back movies perfectly, let alone dispay websites. Hence the newly discovered screen tearing must be a side-effect of switching to xfce4. Initially I thought it was caused by some new driver that got installed or rather replaced during the switch, but there were no signs.

lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)
dpkg -l | grep intel
ii  xserver-xorg-video-intel                                    2:2.99.917+git20160325-1ubuntu1.2                 amd64        X.Org X server -- Intel i8xx, i9xx display driver


After scouring the internet for possible causes such as malconfigured xorg config or wrong drivers and trying to fix these, I saw vertical sync mentioned somewhere and enabling it might help. In xfce4 this feature is found in Settings/Window Manager Tweaks/Compositor/Synchronize drawing to the vertical blank, see in the screenshot below.

Synchronize drawing to the vertical sync
Window manager Tweaks
Make sure to tick the selected "Synchronize drawing to the vertical blank" tickbox and the tearing should be gone.

Tuesday, June 12, 2018

Set date and time in raspbian


My new installation of raspbian stretch had its time off. The easiest way of setting this right I found was using timedatectl.

      Local time: Tue 2018-06-12 18:27:41 UTC
  Universal time: Tue 2018-06-12 18:27:41 UTC
        RTC time: n/a
       Time zone: Etc/UTC (UTC, +0000)

Network time on: yes
NTP synchronized: yes

RTC in local TZ: no

The date was correct but the actual time was off. Checking the output of timedatectl, the time zone was here off, so that was the obvious problem.


Checking the help of timedatectl quickly led to a resolution.

timedatectl -h
timedatectl [OPTIONS...] COMMAND ...

Query or change system time and date settings.

  -h --help                Show this help message
     --version             Show package version
     --no-pager            Do not pipe output into a pager
     --no-ask-password     Do not prompt for password
  -H --host=[USER@]HOST    Operate on remote host
  -M --machine=CONTAINER   Operate on local container
     --adjust-system-clock Adjust system clock when changing local RTC mode

  status                   Show current time settings
  set-time TIME            Set system time
  set-timezone ZONE        Set system time zone
  list-timezones           Show known time zones
  set-local-rtc BOOL       Control whether RTC is in local time
  set-ntp BOOL             Enable or disable network time synchronization

  1. List the available timezones that can be set with,
    timedatectl list-timezones
    and scroll through the list to find the correct one.
  2. Set your current timezone with,
    timedatectl set-timezone Zone/City
No reboot is required, changes take effect right away.

Thursday, May 10, 2018

Install Gridcoinresearch wallet on the Raspberry Pi 3B

I previously wrote about how to get Gridcoinresearch running under Ubuntu. Since then, the project has advanced and in most cases you can simply install the wallet from a PPA.
I came to realize that this was not the case with my Raspberyy Pi 3 B, running Rasbian stretch. When trying to add a PPA as recommended by Launchpad Gridcoin-stable:
Stable builds for ordinary users for i386, amd64 and armhf. This PPA will lag leisure releases by up to one day to ensure stability. Mandatory upgrades will be released immediately.
The following happens.

sudo add-apt-repository ppa:gridcoin/gridcoin-stableTraceback (most recent call last):  File "/usr/bin/add-apt-repository", line 95, in <module>    sp = SoftwareProperties(options=options)  File "/usr/lib/python3/dist-packages/softwareproperties/", line 109, in __init__    self.reload_sourceslist()  File "/usr/lib/python3/dist-packages/softwareproperties/", line 599, in reload_sourceslist    self.distro.get_sources(self.sourceslist)  File "/usr/lib/python3/dist-packages/aptsources/", line 89, in get_sources    (, self.codename))aptsources.distro.NoDistroTemplateException: Error: could not find a distribution template for Raspbian/stretch

Hence, lets compile from source.

Update 12/06/2018

The latest release of Gridcoin switched to using autogen instead of the old make -f makefile process. The install and update process is less tedious this was, but it takes quite long on a Raspberry Pi 3B. The general method for building and installing it is,
make install
However, to succeed on Raspbian, some packages need to be installed first. Proceed as follows.


BerkleyDB4.8  needs to be installed, exactly! So basically what is available from apt (libdb5.x) is not good. I found a good resource for installing this from source at Below is the solution that worked on my Raspberry Pi.
wget ''tar -xzvf db-4.8.30.NC.tar.gz
cd db-4.8.30.NC/build_unix/

../dist/configure --enable-cxx

make install

And then tell the system where to find db4.8
export BDB_INCLUDE_PATH="/usr/local/BerkeleyDB.4.8/include"
export BDB_LIB_PATH="/usr/local/BerkeleyDB.4.8/lib"
ln -s /usr/local/BerkeleyDB.4.8/lib/ /usr/lib/


After this the building can begin. The first few steps are simple,
sudo apt-get install autoconf
git clone
cd Gridcoin-Research./
When trying to run ./configure I got into trouble with BerkleyDB4.8 still not being detected or perhaps superceeded by a higher version. The solution here was to set the environment variable and link CPPFLAGS and LDFLAGS before running ./configure as,
env CPPFLAGS='-I/usr/local/BerkeleyDB.4.8/include' LDFLAGS='-L/usr/local/BerkeleyDB.4.8/lib' ./configure

Note: As usual, you can run make -j4 to run it on 4 threads, however I had a lot of system hungs with my Raspberry Pi at this point. Maybe the RAM ran out, I am not certain. See if it works for you, but I would recommend you set up some temporary swap as descibed below in "Setting up additional Swap".

--- UPDATE END ---


For those who understand commands and want to get things running qucikly.

sudo apt-get install ntp git build-essential libssl-dev libdb-dev libdb++-dev libqrencode-dev libcurl4-openssl-dev libzip4 libzip-dev libboost1.62-all-dev libminiupnpc-dev
sudo dd if=/dev/zero of=/mnt/2GB.swap bs=1024 count=2097152
sudo mkswap /mnt/2GB.swap
sudo swapon /mnt/2GB.swap
git clone
cd ~/Gridcoin-Research/src
chmod 755 leveldb/build_detect_platform
make -f makefile.unix -j 2 USE_UPNP=- -e PIE=1
strip gridcoinresearchd
sudo cp gridcoinresearchd /usr/bin/gridcoinresearchd
sudo swapoff -a


Although, installing the client is described on the Github page [1] of the project and following it step-by-step will result, in most cases, in a perfect installation, for the raspberry pi it can get tricky.

Install dependencies

Nothing special here, just the dependencies. First do a 
sudo apt-get update && sudo apt-get upgrade
and then
sudo apt-get install ntp git build-essential libssl-dev libdb-dev libdb++-dev libqrencode-dev libcurl4-openssl-dev libzip4 libzip-dev libboost1.62-all-dev libminiupnpc-dev

Setting up additional Swap

I ran into issues with memory during compiling, especially with multiple threads. You can try to skip this step and see if it works, otherwise lets create a 2 GiB swap file. The commands take about 2-4 minutes to finish, so be patient.

sudo dd if=/dev/zero of=/mnt/2GB.swap bs=1024 count=2097152
sudo mkswap /mnt/2GB.swap 
sudo swapon /mnt/2GB.swap

This will create a 2GiB /mnt/2GB.swap file that will be used during compiling.

Clone and compile gridcoinresearchd from Github

Everything is ready to pull gridcoinresearchd from Github and proceed with building it.
git clone
cd ~/Gridcoin-Research/src
chmod 755 leveldb/build_detect_platform 
make -f makefile.unix -j 2 USE_UPNP=- -e PIE=1
strip gridcoinresearchd
sudo cp gridcoinresearchd /usr/bin/gridcoinresearchd
To start gridcoinresearchd type

Note: The compiling (make) takes a while. Be patient.

Tip: "gridcoinresearchd" is a system command now and can be called quickly by starting to type it "grid..." and pressing [TAB]. Also, type gridcoinresearchd help to get a list of available commands with the headless client. The -j 2 option tells make to use 2 CPU cores, this helps speeding up the compiling. Some general practice says that it is fine to use number of CPU x 1.5 to get a good parallel performance, however when using 4-6 threads I ran out of memory and got errors.

Turn off swap

Swap is no longer needed after compiling, so it can be turned off. This helps prolonging the SD card's lifespan by preventing writing to it too often.
sudo swapoff -a


If any dependencies are missing (or, of course, something else is wrong) you will be greeted by an army of error messages. For example,
gridcoin upgrader.h:4:42: fatal error: curl/curl.h: No such file or directory  #include <curl/curl.h> // for downloading
means that there is an issue with curl. It took me a while, but it was not actually curl, but libcurl that has been missing. After installing it with sudo apt-get install libcurl4-openssl-dev, the compiling got past this point.

Or something like this
gridcoin compilation terminated. makefile.unix:137: recipe for target 'obj/rpcrawtransaction.o' failed make: *** [obj/rpcrawtransaction.o] Error 1
Here if I remember the issue was a missing boost library. sudo apt-get install libboost1.62-all-dev fixed the problem in this case.

Of course, these are just two examples, but the rule applies. Check the last few lines of the error message, and see what is missing. You can check whether a package is installed with dpkg -l | grep <PACKAGENAME>.

Of course, if you get stuck somewhere you can feel free to leave a comment below.

[1] -