Upcoming Qt switch to OpenGL ES on arm64

[Riku Voipio]

On Thu, Nov 22, 2018 at 07:14:44PM -0300, Lisandro Damián Nicanor Pérez Meyer wrote:
> El jueves, 22 de noviembre de 2018 18:30:39 -03 Marcin Juszkiewicz escribió:
> > Does it mean that arm64 box with PCI Express graphics card will be not
> > able to use Qt based software? I can put Radeon or NVidia card into my
> > box and use it as a normal OpenGL accelerated desktop (did that already
> > few years ago).

> "Depends". The change is only for software using some specific classes inside 
> libqt5gui5. If your video card supports GLES (aka OpenGL ES) then you should 
> be fine.

Mesa based nouveau, radeon and freedreno should support both - so the
deskop env itself should work I think.

> The real issue here is that *many* arm64 boards currently do not support 
> Desktop OpenGL, but do support GLES.

The boards may or may not support Desktop GL. As far as debian is
concerned, they remain headless devices until they have free drivers.

See, most of the propiertary GLES drivers are craptastic and don't work
with Debians kernel. Even ff you manage to dance the right kernel, device
tree and userspace combo, you may still not get the desktop enviroment
up. And nobody is going to fix the bugs you encounter.

Debian does support Qualcomm based boards with freedreno driver, and
work is progressing with etnaviv for Vivante. Both based on Mesa and
support both OpenGL and GLES. With the MALI reverse engineering active
again, it would seem rather short-sighted and counterproductive to
put lots of energy in supporting the propiertary drivers.

> Also applications using GLU[T] or glew will not be able to compile anymore on 
> arm64. GLU[T] has not been ported to GLES, glew somehow differs in a type 
> definition.

I have an Synquacer box with nvidia card running Lxqt desktop, running
fine most tasks. While none of the apps I run on it seem to be of the
Qt + GLU/glew combo, it would be unfortunate if I ever need to use them.

Riku