Também estou com o mesmo problema.
no arquivo /var/log/syslog aparece:
Jun 1 18:11:55 xxx anacron[3359]: Anacron 2.3 started on 2010-06-01
Jun 1 18:11:55 xxx anacron[3359]: Normal exit (0 jobs run)
Jun 1 18:11:55 xxx kernel: [ 986.944421] CPU0 attaching NULL sched-domain.
Jun 1 18:11:55 xxx kernel: [ 986.944429] CPU1 attaching NULL sched-domain.
Jun 1 18:11:56 xxx kernel: [ 987.000110] CPU0 attaching sched-domain:
Jun 1 18:11:56 xxx kernel: [ 987.000116] domain 0: span 0-1 level SIBLING
Jun 1 18:11:56 xxx kernel: [ 987.000119] groups: 0 (cpu_power = 589) 1 (cpu_power = 589)
Jun 1 18:11:56 xxx kernel: [ 987.000128] domain 1: span 0-1 level MC
Jun 1 18:11:56 xxx kernel: [ 987.000131] groups: 0-1 (cpu_power = 1178)
Jun 1 18:11:56 xxx kernel: [ 987.000138] CPU1 attaching sched-domain:
Jun 1 18:11:56 xxx kernel: [ 987.000141] domain 0: span 0-1 level SIBLING
Jun 1 18:11:56 xxx kernel: [ 987.000144] groups: 1 (cpu_power = 589) 0 (cpu_power = 589)
Jun 1 18:11:56 xxx kernel: [ 987.000150] domain 1: span 0-1 level MC
Jun 1 18:11:56 xxx kernel: [ 987.000153] groups: 0-1 (cpu_power = 1178)
Jun 1 18:11:56 xxx kdm[2682]: X server for display :0 terminated unexpectedlyJun 1 18:11:56 xxx kernel: [ 987.977685] agpgart-via 0000:00:00.0: AGP 3.5 bridge
Jun 1 18:11:56 xxx kernel: [ 987.977715] agpgart-via 0000:00:00.0: putting AGP V3 device into 8x mode
Jun 1 18:11:56 xxx kernel: [ 987.977801] pci 0000:01:00.0: putting AGP V3 device into 8x mode
Jun 1 18:11:57 xxx kdm_greet[3385]: /usr/share/kde4/apps/kdm/faces/.default.face is no valid image
Acho que o problema é naquela linha em negrito mas eu não faço a mínima idéia do que esteja causando isso. Alguém tem alguma idéia de como resolver isso, por favor?