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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - modesetting driver plus DRI3 causes extremely slow scrolling with WebKitGTK+ in accelerated compositing mode"
href="https://bugs.freedesktop.org/show_bug.cgi?id=85064#c42">Comment # 42</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - modesetting driver plus DRI3 causes extremely slow scrolling with WebKitGTK+ in accelerated compositing mode"
href="https://bugs.freedesktop.org/show_bug.cgi?id=85064">bug 85064</a>
from <span class="vcard"><a class="email" href="mailto:carlosgc@gnome.org" title="Carlos Garcia Campos <carlosgc@gnome.org>"> <span class="fn">Carlos Garcia Campos</span></a>
</span></b>
<pre>(In reply to Michel Dänzer from <a href="show_bug.cgi?id=85064#c41">comment #41</a>)
<span class="quote">> (In reply to Carlos Garcia Campos from <a href="show_bug.cgi?id=85064#c40">comment #40</a>)
> > Yes, this is because we use the screen width + 1 to position our window
> > offscreen:
> >
> > WidthOfScreen(screen) + 1, 0, 1, 1,
>
> FWIW, WidthOfScreen is bad anyway because that's just how wide the screen
> happened to be when the X11 display connection was established. The screen
> can be widened after that via the RandR extension, in which case the window
> would become visible.</span >
So, I guess using -1, -1 is still a good idea even if it fixes the problem by
casuality.
<span class="quote">> > and it turns out that simply using -1, -1 as coordinates fixes the problem.
>
> Weird, not sure why that avoids the problem; maybe there's an off-by-one bug
> somewhere which causes the window to be incorrectly considered on-screen. I
> wouldn't recommend relying on that. Also, again I'm not sure that negative
> coordinates can never be visible.</span >
Not sure it's off by one, using -100, -100 also works. Yes, that's more a
workaround to make WebKitGTK+ usable again while we find the right solution.
<span class="quote">>
> So, why does this code use a window instead of a pixmap?</span >
I don't really know it, I'm not a graphics expert.
<span class="quote">> Assuming a window is really the only possibility, (why) can't it set the
> swap interval to 0 via one of the GLX extensions for this, to prevent
> SwapBuffers operations from getting throttled?</span >
I tried using glXSwapIntervalSGI(0); after glXMakeCurrent but didn't help.</pre>
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