System hang under F16

[Bill Murray]

   Dear Fedora group,
               Yesterday I updated the lastest F16 fixes. E.g. 
mesa-dri-drivers-7.11-11.fc16.i686

today, twice, the system has hung completely as I opened a
new window. The new window was different on the two occasions;
emacs last time.
   /var/log/messages has nothing in it.

How should I debug?
      Bill
Kernel: 3.1.1-1.fc16.x86_64
 > lsmod
Module                  Size  Used by
tcp_lp                  2111  0
ebtable_nat             1967  0
ebtables               21732  1 ebtable_nat
ipt_MASQUERADE          2248  3
iptable_nat             4687  1
nf_nat                 18606  2 ipt_MASQUERADE,iptable_nat
xt_CHECKSUM             1277  2
iptable_mangle          1663  1
tun                    14111  2
bridge                 72375  0
stp                     1927  1 bridge
llc                     4754  2 bridge,stp
libafs                658715  2
bnep                   14195  2
bluetooth             202902  7 bnep
lockd                  70080  0
nf_conntrack_netbios_ns     1265  0
xt_physdev              1715  1
nf_conntrack_broadcast     1319  1 nf_conntrack_netbios_ns
nf_conntrack_ipv4       8310  29 iptable_nat,nf_nat
ip6t_REJECT             4008  2
nf_defrag_ipv4          1513  1 nf_conntrack_ipv4
nf_conntrack_ipv6       7714  25
nf_defrag_ipv6          9115  1 nf_conntrack_ipv6
xt_state                1306  51
nf_conntrack           67597  8 
ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_netbios_ns,nf_conntrack_broadcast,nf_conntrack_ipv4,nf_conntrack_ipv6,xt_state
ip6table_filter         1655  1
ip6_tables             16776  1 ip6table_filter
fuse                   61671  5
gspca_ov519            30064  0
gspca_main             18860  1 gspca_ov519
videodev               78689  1 gspca_main
media                  11511  1 videodev
v4l2_compat_ioctl32     7665  1 videodev
snd_usb_audio         105329  2
snd_usbmidi_lib        18071  1 snd_usb_audio
snd_rawmidi            19878  1 snd_usbmidi_lib
snd_hda_codec_analog    82289  1
snd_hda_intel          24072  2
snd_hda_codec          85181  2 snd_hda_codec_analog,snd_hda_intel
snd_hwdep               6264  2 snd_usb_audio,snd_hda_codec
snd_seq                52186  0
snd_seq_device          5941  2 snd_rawmidi,snd_seq
e1000e                174876  0
snd_pcm                78498  3 snd_usb_audio,snd_hda_intel,snd_hda_codec
hp_wmi                  8103  0
sparse_keymap           3358  1 hp_wmi
rfkill                 16336  3 bluetooth,hp_wmi
ppdev                   7360  0
snd_timer              19372  2 snd_seq,snd_pcm
snd                    63124  19 
snd_usb_audio,snd_usbmidi_lib,snd_rawmidi,snd_hda_codec_analog,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_seq,snd_seq_device,snd_pcm,snd_timer
soundcore               6267  1 snd
parport_pc             19600  0
snd_page_alloc          7311  2 snd_hda_intel,snd_pcm
parport                32310  2 ppdev,parport_pc
iTCO_wdt               12024  0
microcode              18539  0
iTCO_vendor_support     2578  1 iTCO_wdt
tpm_infineon            6962  0
serio_raw               4298  0
virtio_net             12856  0
kvm_intel             119162  0
kvm                   328030  1 kvm_intel
nls_utf8                1389  1
sunrpc                201219  2 lockd
udf                    66472  0
crc_itu_t               1547  1 udf
uinput                  7230  0
binfmt_misc             6983  1
usb_storage            45966  4
pata_acpi               3419  0
uas                     7775  0
wmi                     9049  1 hp_wmi
ata_generic             3587  0
i915                  389602  2
drm_kms_helper         26490  1 i915
drm                   194476  3 i915,drm_kms_helper
i2c_algo_bit            4958  1 i915
i2c_core               25728  5 
videodev,i915,drm_kms_helper,drm,i2c_algo_bit
video                  12388  1 i915


-- 
Bill Murray                     ----                       ATLAS
STFC RAL at: Bat 161 1-08, CERN,1211 Meyrin, Geneve 23, Switzerland
   Tel:- CERN +41 22 7670631    or  RAL +44 (0)1235 446256