[Notion-devel] Flash fullscreen and mod_xinerama

[Philipp H. <ph...@ph...>]

Hi,

I haven't had problems with Flash fullscreen in a long time, but I've now 
realized that Flash fullscreen completely stops to work whenever the 
mod_xinerama module is enabled. I have done some digging and I've found one 
reason for this (which by the way is completely unrelated to the one 
supposedly addressed by the well-known kludge[1]).

When Flash fullscreen is triggered, the browser creates an unmanaged window 
win, called "Plugin Container" in my case. We call

ioncore_manage_clientwin(win),

which creates a suitable cwin for the window. We then have the following 
trace:

hook_call_alt
-> clientwin_do_manage_default(cwin)
-> try_fullscreen(cwin, ...)
-> netwm_check_initial_fullscreen(cwin)

It turns out that the plugin container has the _NET_WM_STATE_FULLSCREEN 
property, which is reasonable, so netwm_check_initial_fullscreen will return 
region_screen_of((WRegion*)cwin) and try_fullscreen will proceed to attach the 
cwin to this return value.

And here's the problem: region_screen_of((WRegion*)cwin) just does a bunch of 
((WRegion*)cwin)->parent calls until it finds a WScreen. But the way the cwin 
is created, it is an immediate child of the root window. So the upshot is that 
we end up attaching the cwin to the root window. This doesn't cause any 
problems without mod_xinerama as in this case the only screen and the root 
window are identical objects. But with mod_xinerama the only reasonable 
children of the root window are the screens and when we want to fullscreen 
something, we have to attach it to the screen it is on, not to the root 
window.

A suitable screen for the client is already determined in 
clientwin_do_manage_default, so I've simply changed the logic to use this 
screen, see the attached patch. With this Flash fullscreen also works for me 
with mod_xinerama.

Could you guys give this patch a try? Any thoughts? I don't have an actual 
multihead setup so that I might be missing other problems.

Regards,
Philipp

[1] https://sourceforge.net/apps/mediawiki/notion/index.php?title=Configuration#Flash.2FYouTube_Fullscreen