Enable the experimental VC4 stuff via raspi-config first. The stable option 
continues to be the traditional Broadcom stack (and no X11). Though perhaps VC4 
works better these days than it used to, not sure.


Best regards,

Laszlo

________________________________
From: Interest <interest-bounces+laszlo.agocs=qt...@qt-project.org> on behalf 
of Jason H <jh...@gmx.com>
Sent: Thursday, November 8, 2018 8:19 PM
To: Colin Worth
Cc: interest@qt-project.org
Subject: Re: [Interest] Compiling 5.11.2 on a Pi 3B

I really kicked ha hornets nest. Qt5 compiles on Stretch, but it's got terrible 
hardware accleration performance (read: none)

There's no difference for me between xcb and eglfs and glxgears is running at 
30fps.

$ glxgears -info
GL_RENDERER   = Gallium 0.4 on llvmpipe (LLVM 3.9, 128 bits)
GL_VERSION    = 3.0 Mesa 13.0.6
GL_VENDOR     = VMware, Inc.
...
152 frames in 5.0 seconds = 30.357 FPS

$ qtapp -platform eglfs
libEGL warning: DRI2: failed to authenticate
Unable to query physical screen size, defaulting to 100 dpi.
To override, set QT_QPA_EGLFS_PHYSICAL_WIDTH and QT_QPA_EGLFS_PHYSICAL_HEIGHT 
(in millimeters).
Running on a software rasterizer (LLVMpipe), expect limited performance.

What's the best backend to use for Qt on q RPi 3b?

Sent: Thursday, November 08, 2018 at 8:24 AM
From: "Colin Worth" <jlk2...@gmail.com>
To: interest@qt-project.org
Subject: Re: [Interest] Compiling 5.11.2 on a Pi 3B
I cross-compiled latest Qt 5.10.1 for Raspberry Pi 3B on linux a few months 
ago. Disabled es2 configure (-no-eglfs -no-egl). Stretch supports an 
experimental version of OpenGL for the pi, so platform plugin libxcb is okay. 
This is a good starting point: 
https://www.raspberrypi.org/forums/viewtopic.php?t=204529. In addition the 
configure flags, you can also remove references to egl eglfs from 
qtbase/mkspecs/devices/linux-rasp-pi3-vc4-g++/qmake.conf in the source tree. 
Hope this helps.

Colin
On Nov 8, 2018, at 7:24 AM, 
interest-requ...@qt-project.org<mailto:interest-requ...@qt-project.org> wrote:

Re: [Interest] Compiling 5.11.2 on a Pi 3B
_______________________________________________ Interest mailing list 
Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
_______________________________________________
Interest mailing list
Interest@qt-project.org
http://lists.qt-project.org/mailman/listinfo/interest

Reply via email to