I've been asked to post this bug here with reference to the site above.

Copy and paste of non-gentoo specific info from above link:



Using any version of xf86-video-vesa greater than 1.0.1.3 results in not being
able to startx on a S3 Trio card.  Using v1.0.1.3 works fine.

Result:
X Window System Version 7.1.1
Release Date: 12 May 2006
X Protocol Version 11, Revision 0, Release 7.1.1
Build Operating System: Linux 2.6.15-gentoo-r7 i686
Current Operating System: Linux hope-st 2.6.15-gentoo-r7 #1 SMP Wed Mar 29
12:01:30 NZST 2006 i686
Build Date: 27 October 2006
        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Module Loader present
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Fri Oct 27 21:51:38 2006
(==) Using config file: "/etc/X11/xorg.conf"


Fri Oct 27 21:51:38 2006
 vncext:      VNC extension running!
 vncext:      Listening for VNC connections on port 5900
 vncext:      created VNC server for screen 0
    xkb_keycodes             { include "xfree86+aliases(qwerty)" };
    xkb_types                { include "complete" };
    xkb_compatibility        { include "complete" };
    xkb_symbols              { include "pc(pc105)+us" };
    xkb_geometry             { include "pc(pc105)" };

Backtrace:
0: X(xf86SigHandler+0x9d) [0x80c718d]

Fatal server error:
Caught signal 11.  Server aborting

XIO:  fatal IO error 104 (Connection reset by peer) on X server ":0.0"
      after 0 requests (0 known processed) with 0 events remaining.




lspci:
00:05.0 VGA compatible controller: S3 Inc. 86c775/86c785 [Trio 64V2/DX or /GX]
(rev 16)