intel sandy bridge: X session sometimes unrecoverable after screensaver/display powersafe

[Linus van Geuns]

Ubuntu 11.04 x86_64 on a brand new Dell Latitude E6520 with Intel Sandy Bridge integrated GPU.
Sometimes when the screeensaver blanked my screen, the X session wont recover completely:
- Screen reactivates and shows the cursor on a black screen
- nothing happens (waited some minutes)
- switching to consoles is posssible
- when switching back from console to X, mouse pointer shows on top of the consoles frame buffer
- service gdm restarts works (until next display blank)
- did not happen on AC power, yet
- there are i915 hangcheck timer warnings from time to time

Apart from that, I had 2 complete system freezes (X screen freezes, no switch to console, no access via SSH, no ping, ..) within about 2 weeks.

Ah, and I am running virtual machines with KVM and virt-manager almost every day.

-8<-----------------------------------------------------------
$ apt-cache policy xserver-xorg-video-intel
xserver-xorg-video-intel:
  Installed: 2:2.14.0-4ubuntu7.1
  Candidate: 2:2.14.0-4ubuntu7.1
  Version table:
 *** 2:2.14.0-4ubuntu7.1 0
        500 http://de.archive.ubuntu.com/ubuntu/ natty-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     2:2.14.0-4ubuntu7 0
        500 http://de.archive.ubuntu.com/ubuntu/ natty/main amd64 Packages

$ lsb_release -rd
Description: Ubuntu 11.04
Release: 11.04

$ xdriinfo
Screen 0: i965

$ uname -a
Linux rhenium 2.6.38-10-generic #46-Ubuntu SMP Tue Jun 28 15:07:17 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

$ free -m
             total used free shared buffers cached
Mem: 7882 1448 6433 0 63 593
-/+ buffers/cache: 791 7090
Swap: 8191 0 8191

$ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 42
model name : Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz
stepping : 7
cpu MHz : 800.000
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 2
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 x2apic popcnt aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid
bogomips : 5387.55
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:

processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 42
model name : Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz
stepping : 7
cpu MHz : 800.000
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 1
cpu cores : 2
apicid : 2
initial apicid : 2
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 x2apic popcnt aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid
bogomips : 5387.67
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:

processor : 2
vendor_id : GenuineIntel
cpu family : 6
model : 42
model name : Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz
stepping : 7
cpu MHz : 800.000
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 2
apicid : 1
initial apicid : 1
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 x2apic popcnt aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid
bogomips : 5387.67
clflush size : 64
cache_alignment : 64
address sizes : 36 bits physical, 48 bits virtual
power management:

processor : 3
vendor_id : GenuineIntel
cpu family : 6
model : 42
model name : Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz
stepping : 7
cpu MHz : 800.000
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 1
cpu cores : 2
apicid : 3
initial apicid : 3
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 x2apic popcnt aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid
bogomips : 5387.67
clflush size : 64
cache_alignment : 64
address sizes : 36 bits

$ lsmod
Module Size Used by
ppp_deflate 12990 0
zlib_deflate 27074 1 ppp_deflate
bsd_comp 12913 0
ppp_async 17540 1
crc_ccitt 12667 1 ppp_async
option 25285 1
usb_wwan 20407 1 option
usbserial 42908 5 option,usb_wwan
usb_storage 53538 0
uas 17996 0
ip6table_filter 12815 0
ip6_tables 27845 1 ip6table_filter
ipt_MASQUERADE 12759 3
iptable_nat 13182 1
nf_nat 25736 2 ipt_MASQUERADE,iptable_nat
nf_conntrack_ipv4 19640 4 iptable_nat,nf_nat
nf_defrag_ipv4 12729 1 nf_conntrack_ipv4
xt_state 12578 1
nf_conntrack 81956 5 ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_ipv4,xt_state
ipt_REJECT 12576 2
xt_CHECKSUM 12549 1
iptable_mangle 12734 1
xt_tcpudp 12603 5
iptable_filter 12810 1
ip_tables 27456 3 iptable_nat,iptable_mangle,iptable_filter
x_tables 29581 11 ip6table_filter,ip6_tables,ipt_MASQUERADE,iptable_nat,xt_state,ipt_REJECT,xt_CHECKSUM,iptable_mangle,xt_tcpudp,iptable_filter,ip_tables
bridge 82170 0
stp 12931 1 bridge
snd_hda_codec_hdmi 28167 1
snd_hda_codec_idt 71137 1
binfmt_misc 17565 1
rfcomm 47694 8
sco 18187 2
bnep 18308 2
l2cap 53570 16 rfcomm,bnep
arc4 12529 2
kvm_intel 56851 0
kvm 367707 1 kvm_intel
snd_hda_intel 33211 2
snd_hda_codec 103804 3 snd_hda_codec_hdmi,snd_hda_codec_idt,snd_hda_intel
snd_hwdep 13604 1 snd_hda_codec
snd_pcm 96391 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec
snd_seq_midi 13324 0
iwlagn 333717 0
snd_rawmidi 30486 1 snd_seq_midi
btusb 18600 2
cdc_ncm 17501 0
uvcvideo 72195 0
snd_seq_midi_event 14899 1 snd_seq_midi
cdc_acm 22574 0
videodev 82052 1 uvcvideo
bluetooth 72320 9 rfcomm,sco,bnep,l2cap,btusb
cdc_wdm 17506 0
v4l2_compat_ioctl32 17078 1 videodev
iwlcore 167503 1 iwlagn
dell_wmi 12681 0
snd_seq 61621 2 snd_seq_midi,snd_seq_midi_event
usbnet 26165 1 cdc_ncm
mac80211 294370 2 iwlagn,iwlcore
sparse_keymap 13898 1 dell_wmi
ppdev 17113 0
dell_laptop 13827 0
dcdbas 14438 1 dell_laptop
snd_timer 29602 2 snd_pcm,snd_seq
snd_seq_device 14462 3 snd_seq_midi,snd_rawmidi,snd_seq
cfg80211 178528 3 iwlagn,iwlcore,mac80211
snd 67382 14 snd_hda_codec_hdmi,snd_hda_codec_idt,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device
psmouse 73535 0
serio_raw 13166 0
parport_pc 36959 0
soundcore 12680 1 snd
snd_page_alloc 18529 2 snd_hda_intel,snd_pcm
lp 17825 0
parport 46458 3 ppdev,parport_pc,lp
sha256_generic 21031 4
aesni_intel 55161 96
cryptd 20510 33 aesni_intel
aes_x86_64 17208 1 aesni_intel
aes_generic 38279 2 aesni_intel,aes_x86_64
dm_crypt 22993 2
i915 514975 3
sdhci_pci 13989 0
firewire_ohci 40370 0
sdhci 27387 1 sdhci_pci
ahci 25951 3
libahci 26642 1 ahci
drm_kms_helper 42136 1 i915
firewire_core 62646 1 firewire_ohci
crc_itu_t 12707 1 firewire_core
drm 227495 4 i915,drm_kms_helper
e1000e 159096 0
i2c_algo_bit 13400 1 i915
video 19438 1 i915

[Bernhard Bock (bernhard-bock)]

I occasionally have similar symptoms on my Dell E6420 with Sandy Bridge graphics.
As a workaround, it helps to log in via console or ssh and kill the screensaver process.

[Chris Wilson (ickle)]

pageflip versus modeset/DPMS, should be fixed in raring.

[Linus van Geuns (nirkus)]

Bug seems not to be present on precise/12.04 anyway.