Date: Tue, 07 Aug 2012 22:35:59 -0700 From: matt <sendtomatt@gmail.com> To: freebsd-x11@freebsd.org Subject: Re: Problem with new Xorg, radeon & compiz/Kwin revisited Message-ID: <5021FABF.9040802@gmail.com> In-Reply-To: <5021CBD6.6010607@gmail.com> References: <5021CA0E.6080608@gmail.com> <5021CBD6.6010607@gmail.com>
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On 08/07/12 19:15, matt wrote:
>
> A while back, I was having a strange issue with the new Xorg and compiz.
> In a nutshell, closing certain windows caused Xorg to exit on nasty
> signals. At the same time, a few users with Radeon cards were having
> issues with Kwin disabling opengl for no apparent reason.
>
> After some research, I had posted a patch seen in a debian mailing list
> as a possible solution, and it did indeed solve the immediate problem of
> crashing Xorg (and later I found out Kwin worked with OpenGL effects
> when the patch is applied).
>
> It was requested I file a PR but first investigate what issues such a
> patch might cause. I'm glad I waited, because there are a few. The
> medicine is a little worse than the disease. First, with Compiz & Xfce4,
> if X was told to shutdown while the previously affected programs
> (xfce4-terminal running under compiz & xfce4 was obvious), the machine
> would immediately reboot. This is obviously not good. So usually I would
> only logout after closing all windows (except Xfce4-panel and the root
> window). This would work, and the machine could be shut down from the
> TTY.
>
> Recently, I installed KDE4. I was so impressed that I was trying to use
> it as my "daily desktop". OpenGL Kwin was working fine. However,
> engaging the screen lock would reboot the machine, as well as the
> machine occasionally spontaneously rebooting. This was much worse than
> the above issue.
>
> The patch had one other odd effect, which was that Dri2 was disabled for
> some reason.
>
> I reverted the patch to xorg-server I had been running, and now Kwin
> will not start OpenGL mode, because it can't find an ARGBGLX visual. If
> Kwin is started alone, OpenGL suprisingly works. Xfce4+compiz crashes
> Xorg as before, however Dri2 is now enabled. The signal is a segfault at
> 0x0. AIGLX on/off have no effect.
>
> Here was the patch (I applied it manually looking at the file, the
> offsets are wrong for us):
>
> diff --git a/glx/glxdri.c b/glx/glxdri.c
> index 326f539..f6ef784 100644
> --- a/glx/glxdri.c
> +++ b/glx/glxdri.c
> @@ -230,7 +230,7 @@ __glXDRIdrawableDestroy(__GLXdrawable *drawable)
>
> /* If the X window was destroyed, the dri DestroyWindow hook will
> * aready have taken care of this, so only call if pDraw isn't
> NULL. */
> - if (drawable->pDraw != NULL) {
> + if (drawable->pDraw != NULL&& drawable->pDraw->type ==
> DRAWABLE_WINDOW) {
> screen = (__GLXDRIscreen *) glxGetScreen(drawable->pDraw->pScreen);
> (*screen->core->destroyDrawable)(private->driDrawable);
>
> It seems like this shouldn't be having as much effect as it does. I can
> only guess the reboots are from memory problems resulting from lingering
> drawables? I can't explain the Dri2 interaction, nor can I explain
> Kwin's behavior (fairly new to KDE, last time I used it was last century
> :) ).
>
> For what it's worth, my driver is xf86-video-ati on a Radeon HD4650.
> I'm thoroughly confused by this problem and I'd welcome some help trying
> to solve the bug. Anyone else seeing problems with RV710 radeons and
> OpenGL compositing?
>
> Matt
>
>
>
>
A quick follow up...dri2 issue was something else, it works with the
patch. I've tried base gcc as well as gcc47 no difference for
xorg-server and the above behavior. The initial check for pDraw != NULL
was to prevent a double free, and the patch adds a check to prevent an
instance. My best guess now is that there is a double free situation
that passes the DRAWABLE_WINDOW check.
Matt
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