[Mesa-dev] [PATCH v3 0/4] Disable glthread if libX11 isn't thread-safe

[gregory hainaut]

On Fri, 5 May 2017 18:17:22 +0100
Emil Velikov <emil.l.velikov at gmail.com> wrote:

> On 5 May 2017 at 17:58, gregory hainaut <gregory.hainaut at gmail.com> wrote:
> > On Fri, 5 May 2017 17:45:01 +0200
> > Axel Davy <axel.davy at normalesup.org> wrote:
> >  
>  [...]  
> >
> > Hello Axel,
> >
> > Yes it is another possibility. It would requires to track gl calls that end up in X11.
> > I'm not sure if there is an easy way to list all those gl functions. There are at least the
> > draw calls and maybe the clear operations. Besides I'm afraid that we will need to handle
> > various corner cases of the OpenGL API. It is doable but likely more complicated.
> >
> > There is also the Nvidia way, i.e. forces the driver to XInitThreads X11. I think it
> > can be implemented with the help of constructor attribute.
> >  
> Did you trace the above behaviour? What would happen in the following scenario:
>  - There is no link against libGL/libEGL
>  - User gets the dpy primitive w/o calling XInitThreads
>  - Then user dlopens libGL/libEGL, which in itself calls XInitThreads
> At that point it's a bit too late isn't it?
> 
> -Emil

Hello,

No I didn't trace it.

You right, it is too late. You can/must use LD_PRELOAD to ensure that libGL/libEGL is loaded first.

To be honest, the best solution will be to have a thread safe Xlib. No more hack everywhere.

Cheers,
Gregory