I have a notebook with an onboard SiS630 (32Mb shared) and running some 3D 
OpenGL software i get this error:  
   
[sis_tex.c:100]: Failure to allocate texture memory.   
   
i think is related to Mesa and SIS DRI (but not sure), i'm using mesa 6.4.1 and  
Xorg-x11 7.0 modular (last RC available).  
  
here are some useful machine infos:  
  
System uname: 2.6.15-gentoo i686 VIA Samuel 2  
Gentoo Base System version 1.12.0_pre13  
dev-lang/python:     2.3.5-r2, 2.4.2  
sys-apps/sandbox:    1.2.12  
sys-devel/autoconf:  2.13, 2.59-r6  
sys-devel/automake:  1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r1  
sys-devel/binutils:  2.16.1-r1  
sys-devel/libtool:   1.5.20  
virtual/os-headers:  2.6.11-r3  
ACCEPT_KEYWORDS="x86"  
AUTOCLEAN="yes"  
CBUILD="i686-pc-linux-gnu"  
CFLAGS="-march=c3 -O2 -pipe -fno-ident -fomit-frame-pointer  
-momit-leaf-frame-pointer"  
CHOST="i686-pc-linux-gnu"  
CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.4/env /usr/kde/3.4/share/config /usr/kde/3.4/shutdown /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/kde/3/share/config /usr/share/X11/xkb /usr/share/config /var/qmail/control"  
CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d"  
CXXFLAGS="-march=c3 -O2 -pipe -fno-ident -fomit-frame-pointer  
-momit-leaf-frame-pointer"  
DISTDIR="/usr/portage/distfiles"  
FEATURES="autoconfig distlocks fixpackages sandbox sfperms strict"  
GENTOO_MIRRORS="http://gentoo.ngi.it  
http://www.die.unipd.it/pub/Linux/distributions/gentoo-sources"  
LANG="it_IT.UTF-8"  
LC_ALL="it_IT.UTF-8"  
LINGUAS="it"  
MAKEOPTS="-j2 -s"  
PKGDIR="/usr/portage/packages"  
PORTAGE_TMPDIR="/var/tmp"  
PORTDIR="/usr/portage"  
PORTDIR_OVERLAY="/usr/local/portage"  
SYNC="rsync://rsync.gentoo.org/gentoo-portage"  
USE="3dnow 3dnow2 X a52 aac acpi aim alsa apache2 audiofile avi bash-completion  
berkdb bitmap-fonts bmp bzip2 bzlib cairo chroot crypt cups dbus divx4linux dri  
dvd eds emboss encode exif expat ffmpeg fftw firefox flac foomaticdb ftp gd gif  
gimp glut gpg gpm gtk gtk2 gtkhtml hal icq idn imagemagick imap imlib java jpeg  
kde lcms libg++ libwww mad memlimit mhash mikmod mime ming mmap mmx mng motif  
mozsvg mozxmlterm mp3 mpeg msn mysql ncurses nls nptl nptlonly nsplugin objc  
odbc ogg oggvorbis openal opengl pam pam_chroot pcntl pcre pdflib perl php png  
posix postgres pwdb python qmail qt quicktime readline scanner sdl session  
sftplogging simplexml socket spamassassin spell sse ssl svg tiff truetype  
truetype-fonts type1-fonts udev unicode usb vcd vhosts vorbis win32codecs wmf  
x86 xine xml2 xmlrpc xmms xprint xv xvid xvmc yahoo zlib linguas_it  
userland_GNU kernel_linux elibc_glibc"  
Unset:  ASFLAGS, CTARGET, LDFLAGS  
  
  
Xorg.conf driver section:  
  
Section "Device"  
        Identifier  "Card0"  
        Driver      "sis"  
        VendorName  "SiS"  
        BoardName   "SiS 630"  
        BusID       "PCI:1:0:0"  
  
        Option     "AccelMethod"        "EXA"  
        Option     "DRI"                "true"  
        Option     "TurboQueue"         "true"  
        Option     "MaxXFBMem"          "12288"  
        Option     "EnableSiSCtrl"      "true"  
        Option     "MetaModes"          "1024x768-1024x768"  
        Option     "MergedNonRectangular"       "on"  
        Option     "fifo_aggressive"            "true"  
        Option     "AGPSize"            "256"  
        Option     "HWCursor"              "true"  
        Option     "UseColorHWCursor"      "true"  
        Option     "ColorHWCursorBlending" "true"  
EndSection  
  
  
my lspci:  
  
00:00.0 Host bridge: Silicon Integrated Systems [SiS] 630 Host (rev 31)  
00:00.1 IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE] (rev d0)  
00:01.0 ISA bridge: Silicon Integrated Systems [SiS] SiS85C503/5513 (LPC  
Bridge)  
00:01.2 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller  
(rev 07)  
00:01.3 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller  
(rev 07)  
00:01.4 Multimedia audio controller: Silicon Integrated Systems [SiS] SiS PCI  
Audio Accelerator (rev 02)  
00:01.6 Modem: Silicon Integrated Systems [SiS] AC'97 Modem Controller (rev a0)  
00:02.0 PCI bridge: Silicon Integrated Systems [SiS] Virtual PCI-to-PCI bridge  
(AGP)  
00:05.0 Ethernet controller: Realtek Semiconductor Co., Ltd.  
RTL-8139/8139C/8139C+ (rev 10)  
01:00.0 VGA compatible controller: Silicon Integrated Systems [SiS] 630/730  
PCI/AGP VGA Display Adapter (rev 31)  
  
if is needed more infos, tell me. 
thank you very much for the support.