Notes on OLED on Linux

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OLED screens have had issues on Linux. Main problem is unable to control the screen brightness. It looks like there are some ways to do it now

Looks like icc-brightness should help. Install instructions are from here

sudo apt install -y liblcms2-dev
git clone https://github.com/udifuchs/icc-brightness.git
cd icc-brightness
make

You can run the utility with

./icc-brightness

Installing it will set it up to automatically run on log in.

sudo make install

Log out and back in and it should work.

https://appaper.com/oled-laptop-screen-brightness-control-linux/
https://www.reddit.com/r/linux/comments/cmf0vi/the_state_of_oled_brightness_on_linux/

Android Button – Remove Shadow and Border from Button with Image on it

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We can remove the border and shadows from a button by adding the following style code in your activity_main.xml file. Or what ever your XML file is.

style="?android:attr/borderlessButtonStyle"

Code for button. We are setting an image as the background.

  <Button
        android:id="@+id/button"
        style="?android:attr/borderlessButtonStyle"
        android:layout_width="48dp"
        android:layout_height="48dp"
        android:background="@drawable/gear"
        android:onClick="launchSettings"
        android:textSize="12sp"/>

Comparison of buttons. One on the left still has the shadow on it

Difference between border and borderless buttons

More info here

https://stackoverflow.com/questions/28756035/how-to-remove-button-shadow-android
https://stackoverflow.com/questions/27867284/remove-shadow-effect-on-android-button/30856094

UFW Allow ICMP (ping) Traffic

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https://askubuntu.com/questions/6995/how-to-enable-ufw-firewall-to-allow-icmp-response

Open up the UFW before.rules config file

vi /etc/ufw/before.rules

And make sure you have these rules in it

# ok icmp codes for INPUT
-A ufw-before-input -p icmp --icmp-type destination-unreachable -j ACCEPT
-A ufw-before-input -p icmp --icmp-type time-exceeded -j ACCEPT
-A ufw-before-input -p icmp --icmp-type parameter-problem -j ACCEPT
-A ufw-before-input -p icmp --icmp-type echo-request -j ACCEPT
# ok icmp code for FORWARD
-A ufw-before-forward -p icmp --icmp-type destination-unreachable -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type time-exceeded -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type parameter-problem -j ACCEPT
-A ufw-before-forward -p icmp --icmp-type echo-request -j ACCEPT

Getting Android WiFi state in Kotlin

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In Kotlin you can request if the WiFi adapter is on or off with the following code
This changes the text on a textbox, replace with your textbox.

wifiManager = this.applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager
textBox.text = "WiFi State = ${wifiManager.wifiState}"

The important part is 

wifiManager.wifiState

It will return a number from 0-4 which indicates if it is on or off.

0 = WiFi is being disabled
1 = WiFi Disabled
2 = WiFi is being enabled
3 = WiFi is Enabled
4 = Error

https://developer.android.com/reference/kotlin/android/net/wifi/WifiManager#WIFI_STATE_DISABLED:kotlin.Int

Cambium 450 Bandwidth PLL lock lost

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Had a radio briefly showing an error in red on the web page saying “Bandwidth PLL lock lost” The radio seems to operate so not sure if it is an actual issue or maybe an ongoing bug.

Cambium Bandwidth PLL lock lost

These entries are from the cambium 16.1.1 Release Notes
https://community.cambiumnetworks.com/t/450-platform-series-release-16-1-1-is-now-available/65335

  • A very few 450i/450b SMs having “Bandwidth PLL lock lost” and being unable to register to AP on 20 and 30 MHz after upgrade to 16.1.
  • Occasional false positive of 450 radios was showing “Bandwidth PLL lock Lost” but operating normally.

https://community.cambiumnetworks.com/t/pmp450-sm-v16-1-error-bandwidth-pll-lock-lost/63243

Cannot load Zend OPcache – it was already loaded

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Started getting the following error while running ./validate.php for LibreNMS

Cannot load Zend OPcache - it was already loaded

Looks like the problem arises out of PHP trying to load two ini files for OPcache. Was trying to enable OPcache for LibreNMS so I created an opcache.ini file and put the settings in it. I missed the default 10-opcache.ini file.

Moving all the settings into the 10-opcache.ini file and deleting the created opcache.ini file resolved the issue for me.

https://unix.stackexchange.com/questions/253448/php-7-install-throws-cannot-load-zend-opcache-it-was-already-loaded-error/253484

Add ADB path to Windows Environment Variables

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From the start menu search for “Edit environment variables for your account”

Click Path and then Edit.

Edit Environment Variables

Then click new and paste in the path to the ADB directory which should be

%USERPROFILE%\AppData\Local\Android\sdk\platform-tools

And hit OK

Adding ADB path

You should be good now. You’ll need to relaunch and Command Prompts you have open, but you should be able to run adb without having to navigate to the adb folder.

Notes on Migrating UniFi-Video NVR Disk

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Recently upgraded a UniFi-Video VM by creating a new VM and restoring the backup from the previous one. There was a separate virtual disk used for storing all the videos. Although once I reattached it, I had to change the owner to the unifi-video user. lt was reporting that the owner/group was 127 and 134, looks like that was the user ID from the previous VM.

Example output from ls -hla command

drwxr-xr-x 3 127 134 4.0K Jan 16 2020 176de761-8399-3bed-8ceb-917cbe4d25bd
drwxr-xr-x 2 127 134 4.0K Sep 10 12:28 21d506ef-dded-31f2-baf8-c109a7e653b9
drwxr-xr-x 4 127 134 4.0K Jan 1 2020 1a3afc4c-a030-39a1-b139-857444c8b71c

Ended up changing the owner to the unifi-video owner with the chown command. /path/to/videos is the mount point of the video drive.

chown -R unifi-video:unifi-video /path/to/videos

Configuring UFW Firewall on Ubuntu for UniFi and UniFi-Video

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You should be able to copy and paste all the following commands in. You can check the status of the commands after with 

sudo ufw status

Allowing access to UniFi ports

sudo ufw allow 3478/UDP
sudo ufw allow 5514/UDP
sudo ufw allow 8080/TCP
sudo ufw allow 8443/TCP
sudo ufw allow 8880/TCP
sudo ufw allow 8843/TCP
sudo ufw allow 6789/TCP
sudo ufw allow 27117/TCP
sudo ufw allow 10001/UDP
sudo ufw allow 1900/UDP

UniFI Video ports

sudo ufw allow 7080/TCP
sudo ufw allow 7443/TCP
sudo ufw allow 7445/TCP
sudo ufw allow 7446/TCP
sudo ufw allow 7447/TCP
sudo ufw allow 10001/UDP
sudo ufw allow 6666/TCP
sudo ufw allow 7004/UDP
sudo ufw allow 7442/TCP

Helpful links

https://help.ui.com/hc/en-us/articles/217875218-UniFi-Video-Ports-Used
https://help.ui.com/hc/en-us/articles/218506997-UniFi-Ports-Used