Activating Open GL driver on Pi 3?

[tornado]

Hi,

I have tried various steps to activate the experimental Open GL driver, but all end with a blank screen! But using official Raspbian it does work with my hardware.

Has anyone else got it working?

Has the Arch kernel been compiled with the parameters from here?

https://dri.freedesktop.org/wiki/VC4/

I have the latest Arch distribution. I also modified config.txt, added to kernel cmdline.txt, installed the xf86-video-fbturbo driver, and edited the .conf for it in etc/X11/Xorg.conf.d. Still nothing.

You can check the modifications made to the official distro here:

https://github.com/RPi-Distro/raspi-con ... spi-config (1037-1100)

[tornado]

Unfortunately it seems nobody can answer this. I even tried compiling my own 4.5 branch kernel, modules, overlays, and dtb, but couldn't get it to boot.

For now, I'll move to Xubuntu 16.04 Pi, which has OpenGL working very nicely with a simple switch...

[tornado]

ok, can confirm that this now works, the crucial step being removal of Xorg.conf beforehand (and perhaps turbo99.conf).

however, driver is still pretty buggy so hopefully that'll improve with kernel 4.5

[klundry]

Cool! So you do have the VC4 opengl driver working? It accelerates the desktop and everything?

Can you share some more details on the config file changes that are required? Thanks.

[hopchis]

I'd love to know how you got this working on Archlinux for your pi3. I've got a few pis. The pi2 works just as it should with the VC4 driver. If I try using it on a pi3 I get a blank screen every time, regardless of what screen I hook it up to. I even tried putting the microSD card from a pi2 into a pi3, but the same behavior results. I've tried compiling custom kernels, and also tried various additions in the config.txt, but nothing gets a pi3 to work with VC4 with archlinux. Raspbian works with VC4 on the pi3, so surely it should work with Arch too as the various linux distributions are pretty much the same under the hood. The only glaring difference I see between them is the raspbian uses an older kernel--4.1.

If whatever you did to get it to work could possibly get it to work for me, I wish you would share in detail.

[hopchis]

I found a way to solve this.

I know for many arch purists, this may sound terrible--but it works and works really well. I installed rpi-update. Then I ran rpi-update. The firmware and kernel were updated to the latest available from the raspberry pi foundation, which happens to be slightly newer than the arch arm kernel--4.9 instead of 4.8. I rebooted and voila--it works excellently.

So the issue to me seems it must have something to do with kernel configuration options when compiling the kernel. Something about how it is being compiled by arch, or myself when I tried it, is not the same as how raspbian or the pi foundation compiles it, because kernels from either source do work for a pi3 with the VC4 driver. I much prefer using the kernel from rpi-update, of course, because I don't have to be stuck with an older kernel.

[tornado]

Hi,

You should be able to have it working with the Arch kernel as well (currently 4.9.1, but 4.8 when I got it working). The link I put in the first post shows what raspi-config moves around to load the beta GL driver. Of course, you can do those few steps manually.

If your screen is not entirely blank, flashing cursor in top left, then you probably still have an Xorg.conf file.

Also, GL much smoother now, but can crash with certain apps. 700fps in glxgears!

[yangxuan8282]

hi,tornado
If it's necessary to install xf86-video-fbturbo driver?
I am using xf86-video-fbdev now. And did your archlinux has better performance than raspbian?

[hopchis]

Well, Tornado, I don't know how you did it. I am not even trying to get X to boot with the Arch pi kernel yet--I can't get it to boot to the VT without a black screen. I have never had an xorg.conf on any of my pis as I have never needed one. But the inability of my pi3 to boot using vc4 without having a black screen is not going to be related to X at all anyway. I don't know what the answer is to achieve what you claim to have achieved, but I know it is not in Raspbian's raspi-config script. Keeping all other things exactly the same and switching kernels solves the issue for me, without having to worry about spending time banging my head against the wall as I try out different config.txt parameters and other suggestions only to find it still doesn't work. If I do find a solution to make the pi3 work with the archlinux pi kernel while using vc4, I will do it. For now, it doesn't work and I haven't seen anything in hours of searching and research that has been able to change that.

[tornado]

As far as my understanding, the fbturbo is just a more ARM-optimised version of fbdev. If you run the GL driver you should need neither.

Actually, in the latest kernel (4.4.10) I'm back to a blank screen with the GL driver. It wasn't that great anyway. For example, no WebGL in chrome, and crashing back to the login screen sometimes. I'm finding browsing especially quite usable with fbturbo.

Hopefully a smoother experience with 4.5!