Hello,

from time to time, I see the following warning on resume:

[ 7022.245347] PM: Syncing filesystems ... done. [ 7022.271923] PM: Preparing system for mem sleep [ 7022.324107] ------------[ cut here ]------------ [ 7022.324154] WARNING: at drivers/gpu/drm/i915/intel_display.c:1225 intel_crtc_disable+0x52/0x86 [i915]() [ 7022.324155] Hardware name: 2776LEG [ 7022.324157] pipe B assertion failure (expected off, current on) [ 7022.324197] Modules linked in: cdc_mbim(O) cdc_ncm(O) usbnet(O) mii usb_storage uas cdc_acm usbhid hid cdc_wdm netconsole configfs xt_multiport iptable_filter ip_tables rfcomm bnep cpufreq_userspace cpufreq_stats cpufreq_conservative cpufreq_powersave xt_hl binfmt_misc ip6table_filter ip6_tables x_tables fuse nfsd nfs_acl nfs lockd fscache sunrpc 8021q garp stp llc tun ext2 loop btusb bluetooth crc16 iTCO_wdt iTCO_vendor_support snd_hda_codec_conexant snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm arc4 snd_page_alloc iwldvm mac80211 snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_timer snd_seq_device uvcvideo videobuf2_vmalloc thinkpad_acpi psmouse iwlwifi acpi_cpufreq videobuf2_memops lpc_ich coretemp videobuf2_core nvram i2c_i801 qcserial usb_wwan kvm_intel usbserial kvm videodev evdev serio_raw cfg80211 mfd_core rfkill snd ac battery wmi i915 soundcore video drm_kms_helper mei mperf drm processor i2c_algo_bit i2c_core button ext3 mbcache jbd sha256_generic ablk_helper cryptd aes_x86_64 aes_generic cbc dm_crypt dm_mod nbd sg sd_mod sr_mod cdrom crc_t10dif microcode thermal thermal_sys ahci libahci uhci_hcd libata scsi_mod ehci_hcd e1000e usbcore usb_common [last unloaded: mii] [ 7022.324230] Pid: 5161, comm: Xorg Tainted: G W O 3.6.0 #36 [ 7022.324231] Call Trace: [ 7022.324240] [<ffffffff8103e0ed>] ? warn_slowpath_common+0x78/0x8c [ 7022.324243] [<ffffffff8103e19f>] ? warn_slowpath_fmt+0x45/0x4a [ 7022.324262] [<ffffffffa029cce1>] ? intel_crtc_disable+0x52/0x86 [i915] [ 7022.324271] [<ffffffffa01cbf0a>] ? drm_helper_disable_unused_functions+0xf1/0x133 [drm_kms_helper] [ 7022.324277] [<ffffffffa01ccdd0>] ? drm_crtc_helper_set_config+0x185/0x919 [drm_kms_helper] [ 7022.324286] [<ffffffffa01cb738>] ? drm_fb_helper_set_par+0x64/0xac [drm_kms_helper] [ 7022.324294] [<ffffffffa00fc097>] ? journal_add_journal_head+0xa7/0x123 [jbd] [ 7022.324298] [<ffffffff811f6819>] ? fb_set_var+0x274/0x36d [ 7022.324305] [<ffffffffa00f5609>] ? journal_stop+0x203/0x215 [jbd] [ 7022.324319] [<ffffffffa011aaca>] ? __ext3_journal_stop+0x1f/0x3d [ext3] [ 7022.324327] [<ffffffffa010f5fa>] ? ext3_ordered_write_end+0x14b/0x172 [ext3] [ 7022.324331] [<ffffffff811ff487>] ? fbcon_blank+0x6d/0x234 [ 7022.324335] [<ffffffff8125653a>] ? do_unblank_screen+0xff/0x176 [ 7022.324338] [<ffffffff8124d4d5>] ? complete_change_console+0x4b/0xc0 [ 7022.324341] [<ffffffff8124df87>] ? vt_ioctl+0x936/0xfa6 [ 7022.324352] [<ffffffffa01e66ed>] ? drm_ioctl+0x2ed/0x35c [drm] [ 7022.324355] [<ffffffff81245f13>] ? tty_ioctl+0x98a/0x9f7 [ 7022.324358] [<ffffffff81139430>] ? fsnotify+0x231/0x25b [ 7022.324362] [<ffffffff81118bc0>] ? do_vfs_ioctl+0x44b/0x490 [ 7022.324364] [<ffffffff81118c50>] ? sys_ioctl+0x4b/0x6f [ 7022.324368] [<ffffffff8110b367>] ? sys_write+0x45/0x6e [ 7022.324371] [<ffffffff8136f779>] ? system_call_fastpath+0x16/0x1b [ 7022.324373] ---[ end trace fcdef2bbc6ef4c9d ]--- [ 7022.329771] Freezing user space processes ... (elapsed 0.09 seconds) done. [ 7022.426570] Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done. [ 7022.442715] PM: Entering mem sleep [ 7022.442803] Suspending console(s) (use no_console_suspend to debug) [ 7022.445364] uhci_hcd 0000:00:1a.0: power state changed by ACPI to D0

It does not seem to harm, so I have been ignoring it so far. But then I thought you might want to know since you put the warning in there :-)

Grepping through the backups of my kernel logs shows that this started happening around end of July, about the time when I switched from 3.5.0 release candidates to running kernels based on the to-be-v3.6 linux-next. The first time I saw it I was running next-20120726 from linux-next.

But I had a similar warning earlier too:

"panel assertion failure, pipe B regs locked"

This showed up until mid-March when I switched to version 3.2.12-1 of Debians 3.2.0-2-amd64 kernel, which added stable releases v3.2.11 and v3.2.12. Full output of one of those warnings:

Mar 13 09:18:34 nemi kernel: [47373.956730] ------------[ cut here ]------------ Mar 13 09:18:34 nemi kernel: [47373.956776] WARNING: at /build/buildd-linux-2.6_3.2.9-1-amd64-KTPapN/linux-2.6-3.2.9/debian/build/source_amd64_none/drivers/gpu/drm/i915/intel_display.c:915 i9xx_crtc_enable+0x7b/0x1 5a [i915]() Mar 13 09:18:34 nemi kernel: [47373.956780] Hardware name: 2776LEG Mar 13 09:18:34 nemi kernel: [47373.956783] panel assertion failure, pipe B regs locked Mar 13 09:18:34 nemi kernel: [47373.956785] Modules linked in: xt_state ipt_MASQUERADE qmi_wwan(O) bridge iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 nfnetlink_log nfnetlink option usb_wwan usbserial usb_storage uas acpi_cpufreq mperf cpufreq_userspace cpufreq_stats cpufreq_conservative cpufreq_powersave xt_hl ip6t_LOG xt_multiport ip6table_filter iptable_filter ip6_tables ip_tables x_tables parport_pc ppdev lp parport rfcomm bnep binfmt_misc uinput microcode fuse nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc kvm_intel kvm 8021q garp stp tun ext2 coretemp loop btusb bluetooth crc16 snd_hda_codec_conexant joydev snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm thinkpad_acpi snd_seq_midi arc4 snd_rawmidi snd_seq_midi_event iwlwifi snd_seq uvcvideo mac80211 videodev cdc_ether usbnet mii media cdc_wdm(O) snd_timer snd_seq_device cdc_acm v4l2_compat_ioctl32 cfg80211 i915 rfkill evdev drm_kms_helper snd drm i2c_i801 psmouse iTCO_wdt serio_raw iTCO_vendor_support i2c_al Mar 13 09:18:34 nemi kernel: go_bit soundcore snd_page_alloc ac nvram battery power_supply i2c_core wmi video button processor ext3 jbd mbcache sha256_generic cryptd aes_x86_64 aes_generic cbc dm_crypt dm_mod nbd sd_mod crc_t10dif sr_mod cdrom uhci_hcd ahci libahci thermal thermal_sys libata ehci_hcd scsi_mod usbcore e1000e usb_common [last unloaded: qmi_wwan] Mar 13 09:18:34 nemi kernel: [47373.956881] Pid: 27929, comm: kworker/1:1 Tainted: G O 3.2.0-2-amd64 #1 Mar 13 09:18:34 nemi kernel: [47373.956884] Call Trace: Mar 13 09:18:34 nemi kernel: [47373.956892] [<ffffffff81046879>] ? warn_slowpath_common+0x78/0x8c Mar 13 09:18:34 nemi kernel: [47373.956897] [<ffffffff81046925>] ? warn_slowpath_fmt+0x45/0x4a Mar 13 09:18:34 nemi kernel: [47373.956918] [<ffffffffa0269810>] ? assert_panel_unlocked+0x7f/0xc2 [i915] Mar 13 09:18:34 nemi kernel: [47373.956936] [<ffffffffa026e63c>] ? i9xx_crtc_enable+0x7b/0x15a [i915] Mar 13 09:18:34 nemi kernel: [47373.956953] [<ffffffffa026935a>] ? intel_crtc_dpms+0x36/0xf5 [i915] Mar 13 09:18:34 nemi kernel: [47373.956964] [<ffffffffa0248cf0>] ? drm_fb_helper_blank+0x75/0x116 [drm_kms_helper] Mar 13 09:18:34 nemi kernel: [47373.956969] [<ffffffff811d05ae>] ? fb_blank+0x36/0x63 Mar 13 09:18:34 nemi kernel: [47373.956975] [<ffffffff811d9a3f>] ? fbcon_blank+0xe7/0x1c7 Mar 13 09:18:34 nemi kernel: [47373.956980] [<ffffffff81070761>] ? arch_local_irq_save+0x11/0x17 Mar 13 09:18:34 nemi kernel: [47373.956985] [<ffffffff81341734>] ? _raw_spin_lock_irqsave+0x9/0x25 Mar 13 09:18:34 nemi kernel: [47373.956991] [<ffffffff81052022>] ? lock_timer_base.isra.29+0x23/0x47 Mar 13 09:18:34 nemi kernel: [47373.956995] [<ffffffff810522de>] ? __mod_timer+0x139/0x14b Mar 13 09:18:34 nemi kernel: [47373.956999] [<ffffffff8122f6b7>] ? poke_blanked_console+0xac/0xac Mar 13 09:18:34 nemi kernel: [47373.957003] [<ffffffff8122f6b7>] ? poke_blanked_console+0xac/0xac Mar 13 09:18:34 nemi kernel: [47373.957008] [<ffffffff8122ed2a>] ? do_unblank_screen+0xeb/0x144 Mar 13 09:18:34 nemi kernel: [47373.957012] [<ffffffff8122f726>] ? console_callback+0x6f/0xef Mar 13 09:18:34 nemi kernel: [47373.957016] [<ffffffff8105ae4d>] ? process_one_work+0x163/0x284 Mar 13 09:18:34 nemi kernel: [47373.957020] [<ffffffff8105be15>] ? worker_thread+0xc2/0x145 Mar 13 09:18:34 nemi kernel: [47373.957024] [<ffffffff8105bd53>] ? manage_workers.isra.23+0x15b/0x15b Mar 13 09:18:34 nemi kernel: [47373.957028] [<ffffffff8105ef51>] ? kthread+0x76/0x7e Mar 13 09:18:34 nemi kernel: [47373.957033] [<ffffffff81348834>] ? kernel_thread_helper+0x4/0x10 Mar 13 09:18:34 nemi kernel: [47373.957038] [<ffffffff8105eedb>] ? kthread_worker_fn+0x139/0x139 Mar 13 09:18:34 nemi kernel: [47373.957041] [<ffffffff81348830>] ? gs_change+0x13/0x13 Mar 13 09:18:34 nemi kernel: [47373.957044] ---[ end trace 6553f1ddb073fd07 ]--- Mar 13 09:18:34 nemi kernel: [47373.992119] [drm] capturing error event; look for more information in /debug/dri/0/i915_error_state Mar 13 09:18:34 nemi kernel: [47373.995710] render error detected, EIR: 0x00000010 Mar 13 09:18:34 nemi kernel: [47373.995712] IPEIR: 0x00000000 Mar 13 09:18:34 nemi kernel: [47373.995714] IPEHR: 0x00000000 Mar 13 09:18:34 nemi kernel: [47373.995716] INSTDONE: 0xfffffffe Mar 13 09:18:34 nemi kernel: [47373.995717] INSTPS: 0x00000000 Mar 13 09:18:34 nemi kernel: [47373.995719] INSTDONE1: 0xffffffff Mar 13 09:18:34 nemi kernel: [47373.995721] ACTHD: 0x00000000 Mar 13 09:18:34 nemi kernel: [47373.995723] page table error Mar 13 09:18:34 nemi kernel: [47373.995724] PGTBL_ER: 0x00000000

The hardware is a Lenovo X301 laptop with a panel identified as "LTD133EQ1B" and this controller:

00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42] (rev 07) (prog-if 00 [VGA controller]) Subsystem: Lenovo Device [17aa:20e4] Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 45 Region 0: Memory at f0000000 (64-bit, non-prefetchable) [size=4M] Region 2: Memory at d0000000 (64-bit, prefetchable) [size=256M] Region 4: I/O ports at 1800 [size=8] Expansion ROM at <unassigned> [disabled] Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit- Address: fee0300c Data: 4152 Capabilities: [d0] Power Management version 3 Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- Kernel driver in use: i915

00:02.1 Display controller [0380]: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a43] (rev 07) Subsystem: Lenovo Device [17aa:20e4] Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Region 0: Memory at f0400000 (64-bit, non-prefetchable) [size=1M] Capabilities: [d0] Power Management version 3 Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-

Let me know if you want ot have more details about these warnings. Otherwise I'll just keep ignoring them ;-)

Bjørn