When booting the system with display port plugged in, i either get a boot time crash, or X locks up (no reaction to input, but i can ssh in). This is the log from the latter situation [ 267.077299] BUG: unable to handle kernel NULL pointer dereference at (null) [ 267.077342] IP: [< (null)>] (null) [ 267.077364] PGD 222c2d067 PUD 223a5b067 PMD 0 [ 267.077387] Oops: 0010 [#1] SMP [ 267.077404] Modules linked in: msr snd_hda_codec_hdmi snd_hda_codec_conexant snd_hda_codec_generic arc4 iwlmvm i915 mac80211 btusb btrtl btbcm iwlwifi btintel bluetooth drm_kms_helper x86_pkg_temp_thermal coretemp kvm_intel drm kvm squashfs snd_hda_intel snd_hda_codec cfg80211 snd_hwdep snd_hda_core snd_pcm irqbypass crct10dif_pclmul e1000e crc32_pclmul crc32c_intel ghash_clmulni_intel pcspkr serio_raw snd_timer idma64 syscopyarea snd video virt_dma sysfillrect intel_lpss_pci sysimgblt intel_lpss_acpi intel_hid intel_lpss fb_sys_fops mfd_core tpm_infineon sparse_keymap soundcore rfkill i2c_i801 efivarfs dm_zero dm_thin_pool dm_persistent_data dm_bio_prison dm_service_time dm_round_robin dm_queue_length dm_multipath dm_log_userspace dm_flakey dm_delay aesni_intel cbc sha256_generic scsi_transport_iscsi [ 267.077831] virtio_net virtio_ring virtio tg3 libphy sky2 r8169 pcnet32 mii igb ptp pps_core i2c_algo_bit i2c_core dca e1000 bnx2 atl1c fuse nfs lockd grace sunrpc fscache jfs linear raid10 raid1 raid0 dm_raid raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx dm_snapshot dm_bufio dm_crypt dm_mirror dm_region_hash dm_log dm_mod firewire_core crc_itu_t xhci_pci xhci_hcd usb_storage sx8 cciss sr_mod cdrom sg sd_mod ahci libahci [ 267.078110] CPU: 0 PID: 5418 Comm: X Tainted: G U W 4.5.1-gentoo #3 [ 267.078143] Hardware name: HP HP EliteBook 840 G3/8079, BIOS N75 Ver. 01.04 01/31/2016 [ 267.078177] task: ffff88022317d000 ti: ffff880223dbc000 task.ti: ffff880223dbc000 [ 267.078208] RIP: 0010:[<0000000000000000>] [< (null)>] (null) [ 267.078241] RSP: 0018:ffff880223dbfb70 EFLAGS: 00010286 [ 267.078263] RAX: ffff880223dbfc30 RBX: ffff880221477100 RCX: 00000000fffff0a7 [ 267.078284] RDX: 00000000fffff0a7 RSI: ffff8802230c2078 RDI: ffff88007eedb700 [ 267.078301] RBP: ffff880223dbfbf0 R08: ffff88022028f458 R09: 00000000000000a0 [ 267.078318] R10: 00003fffffe00000 R11: ffff88007eedb700 R12: 0000000000000001 [ 267.078337] R13: ffff8802230c4528 R14: ffff8802230c2078 R15: 0000000000000000 [ 267.078372] FS: 00007fb067aa19c0(0000) GS:ffff88022f400000(0000) knlGS:0000000000000000 [ 267.078390] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 267.078403] CR2: 0000000000000000 CR3: 0000000220537000 CR4: 00000000003406f0 [ 267.078419] Stack: [ 267.078432] ffffffffa094ed6f 0000000000000000 ffff8802230c207c fffff0a723086b80 [ 267.078468] ffff880223dbfc30 ffff8802213fa700 ffff880221477100 ffff8802230c4538 [ 267.078488] ffff880223dbfbf0 ffffffffa095eb27 ffff880223dbfbf8 0000000000000000 [ 267.078508] Call Trace: [ 267.078535] [<ffffffffa094ed6f>] ? i915_gem_object_sync+0x17f/0x2f0 [i915] [ 267.078570] [<ffffffffa095eb27>] ? intel_lr_context_do_pin.isra.6+0x77/0xf0 [i915] [ 267.078606] [<ffffffffa096012c>] intel_execlists_submission+0x1ac/0x3f0 [i915] [ 267.078634] [<ffffffffa094204c>] i915_gem_do_execbuffer.isra.13+0xc7c/0xdd0 [i915] [ 267.078662] [<ffffffffa0942e07>] i915_gem_execbuffer2+0xd7/0x250 [i915] [ 267.078689] [<ffffffffa094f9c2>] ? i915_gem_busy_ioctl+0x92/0xe0 [i915] [ 267.078713] [<ffffffffa070a612>] drm_ioctl+0x152/0x540 [drm] [ 267.078737] [<ffffffffa0942d30>] ? i915_gem_execbuffer+0x320/0x320 [i915] [ 267.078755] [<ffffffff81425a83>] ? selinux_file_ioctl+0x113/0x1f0 [ 267.078770] [<ffffffff811d1142>] do_vfs_ioctl+0x92/0x580 [ 267.078783] [<ffffffff8141adb3>] ? security_file_ioctl+0x43/0x60 [ 267.078798] [<ffffffff811d16a9>] SyS_ioctl+0x79/0x90 [ 267.078811] [<ffffffff817ec1db>] entry_SYSCALL_64_fastpath+0x16/0x6e [ 267.078825] Code: Bad RIP value. [ 267.078838] RIP [< (null)>] (null) [ 267.078851] RSP <ffff880223dbfb70> [ 267.078859] CR2: 0000000000000000 [ 267.084838] ---[ end trace 3979714f1ad70e83 ]--- kernel is marked as tainted, possibly due to experiments with i915.semaphores=1 i915.fastboot=1 . I can try other boot options on demand.
The crash does not happen every time, though. If i catch it again, i'll post whatever i find.
Can you confirm your hw, and when it happens again please attach the complete dmesg. (Having the snippet in the comment is great, but it is important to be able look at the history of how we got to that point - even if it just confirms nothing abnormal happens.)
How do i confirm my hw? What does that mean exactly? As for the crash, i got one when trying to run gnome, another attempt let me log into gnome but crashed when i tried to setup displays, external being left to the laptop's screen. I'll see if i can extract the logs out of the machine, as it's completely hard locked.
Created attachment 123337 [details] hard lockup when changing screen layout in gnome partial system log from start of gnome session until the crash when trying to setup multiple monitors. System was booted with display port plugged in, but the monitor plugged to display port is currently used by another computer via hdmi connector.
It seems that the problem is gone with kernel 4.6. No more lockups so far, i'll do some more testing and eventually reopen the bug.
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