Wayland client library thread safety

[darxus at chaosreigns.com]

I guess you're not going to get a useful response here.
That seems really unfortunate to me.  Please open a bug
here, so we at least have a proper record of the problem:
https://bugs.freedesktop.org/enter_bug.cgi?product=Wayland

On 04/19, Arnaud Vrac wrote:
> Hello everyone,
> 
> I am hitting a bug when using Qt5 and wayland on an embedded platform,
> for which I have written a custom EGL backend. The problem is that Qt5
> (QtQuick2 actually) renders in a separate thread, when the wayland
> display has been created in the main thread. I know there is a patch
> for "thread affinity" in qtwayland to solve this, but it is wrong and
> breaks other clients.
> 
> Since it is required from the EGL spec to be able to render in
> multiple threads, how can this be solved ? Does the wayland backend
> for mesa support this properly ? I don't see how it can work since
> even writes in the connection queue are not protected.
> 
> Here is a crude extract from my EGL backends where wayland can fail
> because of thread concurrency:
> 
> - SwapBuffers:
> 
> while (!swap_done) {
>   wl_display_flush()
>   // wait frame callback
>   wl_display_iterate(WL_DISPLAY_READABLE)
> }
> 
> wl_surface_frame()
> wl_surface_attach()
> wl_surface_damage()
> lock_back_buffer()
> swap_buffers()
> 
> - GetBuffers (called on makeCurrent or at the first gl call after swap)
> 
> while (no_buffer_unlocked)
>   wl_display_flush()
>   // wait for a buffer to be released
>   wl_display_iterate(WL_DISPLAY_READABLE)
> }
> 
> Thanks for your help,
> 
> -- 
> rawoul
> _______________________________________________
> wayland-devel mailing list
> wayland-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/wayland-devel
> 

-- 
"For every complex problem, there is a solution that is simple, neat,
and wrong." - H. L. Mencken
http://www.ChaosReigns.com