Comment 1 Peter Åstrand 2013-02-28 11:32:15 CET

Created attachment 466 [details]
xfig.png

Comment 2 Peter Åstrand 2013-02-28 12:38:52 CET

With ThinLinc, the problem happens with both xfig-plain and xfig-Xaw3d. With the CentOS bundled TigerVNC server, it works ok in both cases.

Comment 3 Peter Åstrand 2013-02-28 16:20:46 CET

I've determined that this problem is limited to 64-bit versions of Xvnc. Seems to be a problem in the X server handling of "PolyArc". Haven't found anything obvious, though. Perhaps it is easier to solve bug 3616 instead.

Comment 4 Peter Åstrand 2013-03-04 09:43:36 CET

Note: This is a Xserver problem; not a VNC one. The artefacts are visible even with a "xwd" dump.

Comment 5 Pierre Ossman 2013-04-16 16:29:47 CEST

Problem remains in Xorg 1.14.

Comment 6 Peter Åstrand 2013-04-22 09:37:07 CEST

Created attachment 473 [details]
lollipop-u.fig

Comment 7 Pierre Ossman 2013-04-22 11:29:30 CEST

Also works in Fedora 18's Xvnc.

Oddly enough, it is still broken even if I use Fedora's Xorg source, _and_ Fedora's build environment.

No idea why their version works at this point.

Comment 8 Peter Åstrand 2013-04-22 12:10:44 CEST

There's some difference in which extensions we and RHEL uses:

-Initializing built-in extension VNC
+Initializing built-in extension XINERAMA
+Initializing built-in extension COMPOSITE
+Initializing built-in extension VNC-EXTENSION
+Initializing built-in extension GLX

Comment 9 Peter Åstrand 2013-05-30 16:52:02 CEST

(In reply to comment #8)
> There's some difference in which extensions we and RHEL uses:
> 
> -Initializing built-in extension VNC
> +Initializing built-in extension XINERAMA
> +Initializing built-in extension COMPOSITE
> +Initializing built-in extension VNC-EXTENSION
> +Initializing built-in extension GLX

This is not the problem. After building our new server with:

--disable-xinerama --disable-composite

...the list of extensions are exactly the same, yet the problem occurs in our server but not in the CentOS one.

Comment 10 Peter Åstrand 2013-06-18 20:54:47 CEST

(In reply to comment #7)
> Also works in Fedora 18's Xvnc.
> 
> Oddly enough, it is still broken even if I use Fedora's Xorg source, _and_
> Fedora's build environment.
> 
> No idea why their version works at this point.

Found the difference. The bug is triggered by our CFLAGS containing -O3. Fedora uses -O2.

Comment 11 Peter Åstrand 2013-06-19 10:31:39 CEST

Isolated the problem to the mi directory. Building miarc.c with O2 instead of O3 is required but not sufficient for correct behaviour. Apparently this is a GCC bug:

https://bugs.freedesktop.org/show_bug.cgi?id=47559
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53083

That last bug is still open. In the GCC bugzilla, there are a lot of similar bugs.

Comment 12 Peter Åstrand 2013-06-19 10:50:56 CEST

Workaround in 27538.

Added bug 4711 for tracking the actual GCC problem.

Comment 13 Henrik Andersson 2013-06-24 13:24:57 CEST

Problem is reproducible with 4.1.0 build 3977 using lollipop attachment, but after upgrading to build 3993 it works like a charm.