Ok. I misunderstood your initial message. The situation is a bit more complicated than I thought: you have a dual GPU (or hybrid) setup: an Intel GPU used for basic usage (i.e. desktop software) and an AMD RadeonHD 7500M or 7600M used when you need better specs (i.e. games). By default, the Intel GPU is used so that you have a longer battery life and when more power is needed (launching a game), the laptop is supposed to switch on the AMD GPU. Glxinfo confirms that you’re currently on the Intel GPU.
I’m not really familiar with this kind of setup, especially with AMD GPUs. Intel/nVidia dual setups have Bumblebee/Optimus but I’m not sure what is the equivalent for AMD.
Note that if you search for infos on Google about this (something like “amd hybrid graphics ubuntu”), you might find old messages saying to use the Catalyst proprietary driver to handle the switch automatically. The development of Catalyst (also known as fglrx) has stopped just before the release of Ubuntu 16.04 and if you find an old version, don’t try to install it on a recent Ubuntu, it won’t be compatible and you will break your system. Some docs also talk about vga_switcheroo but it seems to have been removed from recent kernels.
It’s possible that there is currently no way to make the OS automatically switch to the AMD GPU on hybrid setups. I’ve found a video that explains how to switch the GPU manually but it’s not very convenient to do this.
I’m not really able to help you more on this, as I’ve never used a hybrid setup, maybe there’s someone around who has more experience about this.