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Kukkimonsuta / rpi-buildqt

Guide for cross compiling QT 5.8 with piomxtextures for raspberry pi
MIT License
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New opengl drivers makes applications to fail starting #18

Open maitredede opened 7 years ago

maitredede commented 7 years ago

Hi, In raspi-config, when activating the new OpenGL driver, the Qt applications does not start anymore. The error message is * failed to add service - already in use?. There are 3 possible choices : full, fake or legacy. Only the legacy works, others show error message.

KK1423 commented 7 years ago

Qt applications are already hardware accelerated using the eglfs graphics backend, which uses the vchiq device directly. The modification that raspi-config makes to config.txt, adding the device tree overlay, causes the experimental driver to claim the device for itself. Removing the overlay from the end of /boot/config.txt and rebooting solves this problem. If you're using Qt with eglfs then the driver won't be needed anyways.

maitredede commented 7 years ago

@KK1423 ok, that seams logic, but since I have suttering with the legacy driver, I wondered if using the new driver could be more performant. Also WebGL seams to not be available...

KK1423 commented 7 years ago

As far as I understand, eglfs based qt applications will not run with the gl driver enabled. It seems that you will just need to switch back and forth if you want desktop accelerated desktop opengl performance.

KK1423 commented 7 years ago

Actually, there is a mkspec to build Qt to support the experimental drivers. Sorry about that. Try replacing the linux-rasp-pi3-g++ in line 27 of the build script with linux-rasp-pi3-vc4-g++ and see if that build works with the GL drivers.