I have lightDM set to auto-login into my XFCE session, and then XFCE locks the screen after login. This first lock works fine. However, the next time the session locks, the screen blanks as it should, but stays on. (I have the machine set to turn off the screen). I can not get any graphical response out of the system - switching TTYs doesn't work, CTRL+ALT+DEL doesn't achieve anything, but Alt+SysReq does work. The machine still runs - existing ssh sessions continue to work, but logging onto the machine after the crash causes ssh to freeze, and remain unresponsive to CTRL+C. Debian testing x64, running on a Libreboot Thinkpad X200 (GM45 express chipset) - this crash does not happen on 4.3.x. Happens on both 4.4 and 4.4.1 The following appears in journald: Feb 02 17:48:03 x200 acpid[835]: client 2533[0:0] has disconnected Feb 02 17:48:04 x200 systemd-logind[836]: Removed session c1. Feb 02 17:48:04 x200 systemd[1]: Stopping User Manager for UID 129... Feb 02 17:48:04 x200 systemd[2551]: Stopped target Default. Feb 02 17:48:04 x200 systemd[2551]: Reached target Shutdown. Feb 02 17:48:04 x200 systemd[2551]: Starting Exit the Session... Feb 02 17:48:04 x200 systemd[2551]: Stopped target Basic System. Feb 02 17:48:04 x200 systemd[2551]: Stopped target Timers. Feb 02 17:48:04 x200 systemd[2551]: Stopped target Sockets. Feb 02 17:48:04 x200 systemd[2551]: Stopped target Paths. Feb 02 17:48:04 x200 systemd[2551]: Received SIGRTMIN+24 from PID 2612 (kill). Feb 02 17:48:04 x200 systemd[1]: Stopped User Manager for UID 129. Feb 02 17:48:04 x200 systemd[1]: Removed slice User Slice of lightdm. Feb 02 17:48:06 x200 kernel: ------------[ cut here ]------------ Feb 02 17:48:06 x200 kernel: WARNING: CPU: 1 PID: 1209 at include/linux/kref.h:46 drm_framebuffer_reference+0x40/0x70() Feb 02 17:48:06 x200 kernel: Modules linked in: rfcomm fuse bnep cdc_ether usbnet mii cdc_wdm cdc_acm kvm_intel kvm irqbypass ath3k sr_mod cdrom btusb btintel bluetooth ath9k ath9k_common ath9k_hw ath snd_hda_codec_conexant e1000e lp Feb 02 17:48:06 x200 kernel: CPU: 1 PID: 1209 Comm: Xorg Tainted: G I 4.4.1-nr44-x200-r1454398010+ #1 Feb 02 17:48:06 x200 kernel: Hardware name: LENOVO 7458AW5/7458AW5, BIOS CBET4000 libreboot-r20150518fix-688-gbcf3ffd 01/25/2016 Feb 02 17:48:06 x200 kernel: ffffffff819aa6c7 ffffffff81304153 0000000000000000 ffffffff81055fbd Feb 02 17:48:06 x200 kernel: ffff88022d87f580 ffff88022d8d6700 ffff88022d8d6700 ffff88022d783000 Feb 02 17:48:06 x200 kernel: ffff88022d856000 ffffffff814061e0 ffff88022d87f580 ffffffff81417248 Feb 02 17:48:06 x200 kernel: Call Trace: Feb 02 17:48:06 x200 kernel: [<ffffffff81304153>] ? dump_stack+0x40/0x5d Feb 02 17:48:06 x200 kernel: [<ffffffff81055fbd>] ? warn_slowpath_common+0x7d/0xb0 Feb 02 17:48:06 x200 kernel: [<ffffffff814061e0>] ? drm_framebuffer_reference+0x40/0x70 Feb 02 17:48:06 x200 kernel: [<ffffffff81417248>] ? drm_atomic_set_fb_for_plane+0x28/0x80 Feb 02 17:48:06 x200 kernel: [<ffffffff813f53b5>] ? __drm_atomic_helper_set_config+0xb5/0x3a0 Feb 02 17:48:06 x200 kernel: [<ffffffff813f71ff>] ? drm_fb_helper_pan_display+0x17f/0x220 Feb 02 17:48:06 x200 kernel: [<ffffffff814a3ce6>] ? intel_fbdev_pan_display+0x16/0x60 Feb 02 17:48:06 x200 kernel: [<ffffffff813656f3>] ? soft_cursor+0x193/0x210 Feb 02 17:48:06 x200 kernel: [<ffffffff81369e19>] ? fb_pan_display+0xc9/0x150 Feb 02 17:48:06 x200 kernel: [<ffffffff8136496a>] ? bit_update_start+0x1a/0x40 Feb 02 17:48:06 x200 kernel: [<ffffffff81361bb7>] ? fbcon_switch+0x397/0x5d0 Feb 02 17:48:06 x200 kernel: [<ffffffff813cbf01>] ? redraw_screen+0x171/0x250 Feb 02 17:48:06 x200 kernel: [<ffffffff81360f68>] ? fbcon_blank+0x108/0x2f0 Feb 02 17:48:06 x200 kernel: [<ffffffff813cd308>] ? do_unblank_screen+0xd8/0x1a0 Feb 02 17:48:06 x200 kernel: [<ffffffff813c2e54>] ? complete_change_console+0x54/0xd0 Feb 02 17:48:06 x200 kernel: [<ffffffff813c3579>] ? vt_ioctl+0x6a9/0x1270 Feb 02 17:48:06 x200 kernel: [<ffffffff813fdbf2>] ? drm_ioctl+0x162/0x4c0 Feb 02 17:48:06 x200 kernel: [<ffffffff813b77b5>] ? tty_ioctl+0x335/0xbb0 Feb 02 17:48:06 x200 kernel: [<ffffffff811a80c8>] ? do_vfs_ioctl+0x298/0x470 Feb 02 17:48:06 x200 kernel: [<ffffffff811964f6>] ? vfs_write+0x156/0x190 Feb 02 17:48:06 x200 kernel: [<ffffffff811a8314>] ? SyS_ioctl+0x74/0x80 Feb 02 17:48:06 x200 kernel: [<ffffffff81797c9b>] ? entry_SYSCALL_64_fastpath+0x16/0x6a Feb 02 17:48:06 x200 kernel: ---[ end trace 28390e893bc89ee8 ]--- Feb 02 17:48:06 x200 kernel: BUG: unable to handle kernel NULL pointer dereference at 00000000000002e8 Feb 02 17:48:06 x200 kernel: IP: [<ffffffff8179606e>] mutex_lock+0xe/0x30 Feb 02 17:48:06 x200 kernel: PGD 0 Feb 02 17:48:06 x200 kernel: Oops: 0002 [#1] SMP Feb 02 17:48:06 x200 kernel: Modules linked in: rfcomm fuse bnep cdc_ether usbnet mii cdc_wdm cdc_acm kvm_intel kvm irqbypass ath3k sr_mod cdrom btusb btintel bluetooth ath9k ath9k_common ath9k_hw ath snd_hda_codec_conexant e1000e lp Feb 02 17:48:06 x200 kernel: CPU: 1 PID: 1209 Comm: Xorg Tainted: G W I 4.4.1-nr44-x200-r1454398010+ #1 Feb 02 17:48:06 x200 kernel: Hardware name: LENOVO 7458AW5/7458AW5, BIOS CBET4000 libreboot-r20150518fix-688-gbcf3ffd 01/25/2016 Feb 02 17:48:06 x200 kernel: task: ffff88022d7a6140 ti: ffff88022dbb8000 task.ti: ffff88022dbb8000 Feb 02 17:48:06 x200 kernel: RIP: 0010:[<ffffffff8179606e>] [<ffffffff8179606e>] mutex_lock+0xe/0x30 Feb 02 17:48:06 x200 kernel: RSP: 0018:ffff88022dbbba38 EFLAGS: 00010286 Feb 02 17:48:06 x200 kernel: RAX: 0000000000000000 RBX: 00000000000002e8 RCX: ffff8802ad8d6700 Feb 02 17:48:06 x200 kernel: RDX: 0000000080000000 RSI: ffff8800bb36b400 RDI: 00000000000002e8 Feb 02 17:48:06 x200 kernel: RBP: 0000000000000000 R08: ffffea0002ea091f R09: 0000000000000007 Feb 02 17:48:06 x200 kernel: R10: ffff88020c3d0100 R11: ffff88020c35a780 R12: 00000000000002e8 Feb 02 17:48:06 x200 kernel: R13: ffff88022d87f580 R14: ffff88022d83b800 R15: ffff88022e32ee38 Feb 02 17:48:06 x200 kernel: FS: 00007f0f1b4eca00(0000) GS:ffff880237d00000(0000) knlGS:0000000000000000 Feb 02 17:48:06 x200 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b Feb 02 17:48:06 x200 kernel: CR2: 00000000000002e8 CR3: 000000022d5f6000 CR4: 00000000000406e0 Feb 02 17:48:06 x200 kernel: Stack: Feb 02 17:48:06 x200 kernel: ffff88022d87f588 ffffffff81406147 ffff8800bb36b400 0000000000000002 Feb 02 17:48:06 x200 kernel: 0000000000000002 ffff88022d84d800 ffff88022d83b800 ffffffff813f35a7 Feb 02 17:48:06 x200 kernel: ffff8800ba5d9c00 ffffffff81415edf ffff8800ba5d9c00 ffff88022d84d800 Feb 02 17:48:06 x200 kernel: Call Trace: Feb 02 17:48:06 x200 kernel: [<ffffffff81406147>] ? drm_framebuffer_free+0x27/0x80 Feb 02 17:48:06 x200 kernel: [<ffffffff813f35a7>] ? drm_atomic_helper_plane_destroy_state+0x17/0x20 Feb 02 17:48:06 x200 kernel: [<ffffffff81415edf>] ? drm_atomic_state_default_clear+0xff/0x150 Feb 02 17:48:06 x200 kernel: [<ffffffff8147761e>] ? intel_atomic_state_clear+0xe/0x20 Feb 02 17:48:06 x200 kernel: [<ffffffff814165e7>] ? drm_atomic_state_free+0x17/0x60 Feb 02 17:48:06 x200 kernel: [<ffffffff813f727c>] ? drm_fb_helper_pan_display+0x1fc/0x220 Feb 02 17:48:06 x200 kernel: [<ffffffff814a3ce6>] ? intel_fbdev_pan_display+0x16/0x60 Feb 02 17:48:06 x200 kernel: [<ffffffff813656f3>] ? soft_cursor+0x193/0x210 Feb 02 17:48:06 x200 kernel: [<ffffffff81369e19>] ? fb_pan_display+0xc9/0x150 Feb 02 17:48:06 x200 kernel: [<ffffffff8136496a>] ? bit_update_start+0x1a/0x40 Feb 02 17:48:06 x200 kernel: [<ffffffff81361bb7>] ? fbcon_switch+0x397/0x5d0 Feb 02 17:48:06 x200 kernel: [<ffffffff813cbf01>] ? redraw_screen+0x171/0x250 Feb 02 17:48:06 x200 kernel: [<ffffffff81360f68>] ? fbcon_blank+0x108/0x2f0 Feb 02 17:48:06 x200 kernel: [<ffffffff813cd308>] ? do_unblank_screen+0xd8/0x1a0 Feb 02 17:48:06 x200 kernel: [<ffffffff813c2e54>] ? complete_change_console+0x54/0xd0 Feb 02 17:48:06 x200 kernel: [<ffffffff813c3579>] ? vt_ioctl+0x6a9/0x1270 Feb 02 17:48:06 x200 kernel: [<ffffffff813fdbf2>] ? drm_ioctl+0x162/0x4c0 Feb 02 17:48:06 x200 kernel: [<ffffffff813b77b5>] ? tty_ioctl+0x335/0xbb0 Feb 02 17:48:06 x200 kernel: [<ffffffff811a80c8>] ? do_vfs_ioctl+0x298/0x470 Feb 02 17:48:06 x200 kernel: [<ffffffff811964f6>] ? vfs_write+0x156/0x190 Feb 02 17:48:06 x200 kernel: [<ffffffff811a8314>] ? SyS_ioctl+0x74/0x80 Feb 02 17:48:06 x200 kernel: [<ffffffff81797c9b>] ? entry_SYSCALL_64_fastpath+0x16/0x6a Feb 02 17:48:06 x200 kernel: Code: 5f 5d c3 31 c0 87 03 83 f8 01 0f 85 66 ff ff ff eb d1 90 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 53 48 89 fb e8 c2 e8 ff ff <f0> ff 0b 79 08 48 89 df e8 e5 fe ff ff 65 48 8b 04 25 80 ae 00 Feb 02 17:48:06 x200 kernel: RIP [<ffffffff8179606e>] mutex_lock+0xe/0x30 Feb 02 17:48:06 x200 kernel: RSP <ffff88022dbbba38> Feb 02 17:48:06 x200 kernel: CR2: 00000000000002e8 Feb 02 17:48:06 x200 kernel: ---[ end trace 28390e893bc89ee9 ]--- Feb 02 17:48:06 x200 pulseaudio[2046]: [pulseaudio] module-alsa-card.c: Failed to find a working profile. Feb 02 17:48:06 x200 pulseaudio[2046]: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="29" name="platform-thinkpad_acpi" card_name="alsa_card.platform-thinkpad_acpi" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.
Please file new i915 bugs at the freedesktop.org bugzilla https://bugs.freedesktop.org/enter_bug.cgi?product=DRI&component=DRM/Intel