The current stable kernel/firmware limits the GPU overclocking. I think a new firmware is necessary to be able to overclock the GPU again - there was a forum topic a few days ago with details. Why are you overclocking your PI ?
@mitu I'm overclocking to increase dreamcast and N64 performances. I noticed that with that OC values my pi stays under 70 Celsius degrees and dreamcast games run very well. I hope to gain some frame overclocking GPU as well but from what I understood it's not so affecting.
I know this topic is pretty old but I just had this happen to me. It happened because of a conflict in RetroPie auto start. I had manually entered a command line to auto start and then later chose the auto start option in RetroPie setup. Seems the two didn’t work well together. I resolved it by getting back to RetroPie setup in command line and deleted the auto start line. I’m definitely a noob so I apologize if my terminology is wrong. But I’m learning. Hope this helps someone else.
What kind of hardware acceleration are you talking about exactly ? What you need exactly ? There are different kinds.
Yes you can enable the OpenGL open-source driver, and chromium will say that GPU acceleration is active, but from my tests, there are no benefits of running Chromium with the OpenGL open-source driver unless you need WebGL, for the contrary, you will loose video hardware acceleration for example.
If there is a way to use OpenGL on RetroPie, short awnser is no. At least not an easy way, and even if you could make some emulators work, it would be worse using de open-source driver.