Android Studio: Running application in emulator not working

Yesterday I downloaded Android Studio for my Debian Testing system. I wanted to run a HelloWorld application (just a blank activity) but weren't able to run it. With adb I can install it without having any problems. However, if I try to do it with Android Studio, it gets stuck on 'Installing APKs'. The same happens when I try to start it in an emulator (gets stuck on 'Waiting for target device to come online'). My device is a Samsung Galaxy S3 with LineageOS (Android 7.1.2) and root permissions. Android Studio recognizes my phone properly. What I've already done: - installed with openjdk - installed with oracle jdk - set android_home - installed all the SDK-platforms since Android 4.3 and Android Emulator from SDK tool - installed everything from SDK tool - enabled USB-debugging - tried with MTP and PTP - tried another emulated phone - installed lib32stdc++6 - restarted my computer - created new blank activity - reinstalled everything: JDK, Android SDK and Android Studio - and probably much more I do not get any error. Today I managed to have the emulator start by setting graphics to software but it just shows a black screen and doesn't power on. I tried to do it until now and couldn't find a solution. I have never experienced anything close to this on other systems. I really would like to get it running on Debian because I do not want to install Windows for this. I remember that I was able to run it on LMDE2 some time ago. So why doesn't it work on Debian Testing now? Did I forget something? Thank you in advance. **EDIT:** I am now able to use my phone to run the android application by using USB 2.0 instead of USB 3.0! Is that a normal behavior since it works with native adb? I mean, if I buy a new PC after some years which has got only USB 3.0 ports, will I not be able to use phone debugging with Android Studio or is this just an issue? It is still known since 2014 (https://stackoverflow.com/a/9548311/8292104) . However, I still cannot get the app running on an ADV. I changed graphics to software, now it shows the phone but the screen remains black and the phone won't start. What can I do to fix it?