I experience a similar problem with my Dell System XPS L322X (Ubuntu developer laptop). It occurs when I first connect with my TV usin HDMI (with a DisplayPort adapter) and then connect to an external monitor using DisplayPort (without an adapter).
This is perhaps a relevant section of syslog: --- Apr 16 22:36:20 barnabas kernel: [18799.110699] [drm:intel_cpt_verify_modeset] *ERROR* mode set failed: pipe 1 stuck Apr 16 22:38:37 barnabas kernel: [18935.641681] INFO: task Xorg:1301 blocked for more than 120 seconds. Apr 16 22:38:37 barnabas kernel: [18935.641691] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Apr 16 22:38:37 barnabas kernel: [18935.641695] Xorg D ffff88023f2d39c0 0 1301 1243 0x00400004 Apr 16 22:38:37 barnabas kernel: [18935.641705] ffff880233365ba8 0000000000000082 ffff88022f49ae00 ffff880233365fd8 Apr 16 22:38:37 barnabas kernel: [18935.641714] ffff880233365fd8 ffff880233365fd8 ffff880190168000 ffff88022f49ae00 Apr 16 22:38:37 barnabas kernel: [18935.641720] 0000000000000286 ffff880232b26800 ffff88022e66edf0 ffff88022ec25000 Apr 16 22:38:37 barnabas kernel: [18935.641727] Call Trace: Apr 16 22:38:37 barnabas kernel: [18935.641747] [<ffffffff816808b9>] schedule+0x29/0x70 Apr 16 22:38:37 barnabas kernel: [18935.641807] [<ffffffffa00af0c5>] intel_crtc_wait_for_pending_flips+0x75/0xd0 [i915] Apr 16 22:38:37 barnabas kernel: [18935.641818] [<ffffffff810769d0>] ? finish_wait+0x80/0x80 Apr 16 22:38:37 barnabas kernel: [18935.641853] [<ffffffffa00b1b15>] ironlake_crtc_disable+0x55/0x790 [i915] Apr 16 22:38:37 barnabas kernel: [18935.641883] [<ffffffffa00b22de>] ironlake_crtc_dpms+0x8e/0xa0 [i915] Apr 16 22:38:37 barnabas kernel: [18935.641912] [<ffffffffa00ad7b8>] intel_crtc_dpms+0x48/0x140 [i915] Apr 16 22:38:37 barnabas kernel: [18935.641940] [<ffffffffa00ad770>] ? ironlake_update_plane+0x250/0x250 [i915] Apr 16 22:38:37 barnabas kernel: [18935.641974] [<ffffffffa00bf1c0>] ? intel_dp_commit+0xb0/0xb0 [i915] Apr 16 22:38:37 barnabas kernel: [18935.641993] [<ffffffffa007ba97>] drm_helper_connector_dpms+0x107/0x130 [drm_kms_helper] Apr 16 22:38:37 barnabas kernel: [18935.642029] [<ffffffffa002f03d>] drm_mode_obj_set_property_ioctl+0x32d/0x340 [drm] Apr 16 22:38:37 barnabas kernel: [18935.642060] [<ffffffffa002f080>] drm_mode_connector_property_set_ioctl+0x30/0x40 [drm] Apr 16 22:38:37 barnabas kernel: [18935.642089] [<ffffffffa001c6d3>] drm_ioctl+0x4d3/0x580 [drm] Apr 16 22:38:37 barnabas kernel: [18935.642121] [<ffffffffa002f050>] ? drm_mode_obj_set_property_ioctl+0x340/0x340 [drm] Apr 16 22:38:37 barnabas kernel: [18935.642131] [<ffffffff811c11bb>] ? fsnotify+0x24b/0x340 Apr 16 22:38:37 barnabas kernel: [18935.642140] [<ffffffff81194349>] do_vfs_ioctl+0x99/0x590 Apr 16 22:38:37 barnabas kernel: [18935.642148] [<ffffffff811a0ce4>] ? mntput+0x24/0x40 Apr 16 22:38:37 barnabas kernel: [18935.642155] [<ffffffff81183b12>] ? fput+0x1a2/0x260 Apr 16 22:38:37 barnabas kernel: [18935.642162] [<ffffffff811948d9>] sys_ioctl+0x99/0xa0 Apr 16 22:38:37 barnabas kernel: [18935.642173] [<ffffffff81689a69>] system_call_fastpath+0x16/0x1b Apr 16 22:40:37 barnabas kernel: [19055.486247] INFO: task Xorg:1301 blocked for more than 120 seconds. Apr 16 22:40:37 barnabas kernel: [19055.486256] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Apr 16 22:40:37 barnabas kernel: [19055.486261] Xorg D ffff88023f2d39c0 0 1301 1243 0x00400004 Apr 16 22:40:37 barnabas kernel: [19055.486270] ffff880233365ba8 0000000000000082 ffff88022f49ae00 ffff880233365fd8 Apr 16 22:40:37 barnabas kernel: [19055.486279] ffff880233365fd8 ffff880233365fd8 ffff880190168000 ffff88022f49ae00 Apr 16 22:40:37 barnabas kernel: [19055.486285] 0000000000000286 ffff880232b26800 ffff88022e66edf0 ffff88022ec25000 Apr 16 22:40:37 barnabas kernel: [19055.486292] Call Trace: Apr 16 22:40:37 barnabas kernel: [19055.486310] [<ffffffff816808b9>] schedule+0x29/0x70 Apr 16 22:40:37 barnabas kernel: [19055.486368] [<ffffffffa00af0c5>] intel_crtc_wait_for_pending_flips+0x75/0xd0 [i915] Apr 16 22:40:37 barnabas kernel: [19055.486379] [<ffffffff810769d0>] ? finish_wait+0x80/0x80 Apr 16 22:40:37 barnabas kernel: [19055.486412] [<ffffffffa00b1b15>] ironlake_crtc_disable+0x55/0x790 [i915] Apr 16 22:40:37 barnabas kernel: [19055.486443] [<ffffffffa00b22de>] ironlake_crtc_dpms+0x8e/0xa0 [i915] Apr 16 22:40:37 barnabas kernel: [19055.486472] [<ffffffffa00ad7b8>] intel_crtc_dpms+0x48/0x140 [i915] Apr 16 22:40:37 barnabas kernel: [19055.486500] [<ffffffffa00ad770>] ? ironlake_update_plane+0x250/0x250 [i915] Apr 16 22:40:37 barnabas kernel: [19055.486535] [<ffffffffa00bf1c0>] ? intel_dp_commit+0xb0/0xb0 [i915] Apr 16 22:40:37 barnabas kernel: [19055.486556] [<ffffffffa007ba97>] drm_helper_connector_dpms+0x107/0x130 [drm_kms_helper] Apr 16 22:40:37 barnabas kernel: [19055.486591] [<ffffffffa002f03d>] drm_mode_obj_set_property_ioctl+0x32d/0x340 [drm] Apr 16 22:40:37 barnabas kernel: [19055.486621] [<ffffffffa002f080>] drm_mode_connector_property_set_ioctl+0x30/0x40 [drm] Apr 16 22:40:37 barnabas kernel: [19055.486651] [<ffffffffa001c6d3>] drm_ioctl+0x4d3/0x580 [drm] Apr 16 22:40:37 barnabas kernel: [19055.486682] [<ffffffffa002f050>] ? drm_mode_obj_set_property_ioctl+0x340/0x340 [drm] Apr 16 22:40:37 barnabas kernel: [19055.486693] [<ffffffff811c11bb>] ? fsnotify+0x24b/0x340 Apr 16 22:40:37 barnabas kernel: [19055.486702] [<ffffffff81194349>] do_vfs_ioctl+0x99/0x590 Apr 16 22:40:37 barnabas kernel: [19055.486710] [<ffffffff811a0ce4>] ? mntput+0x24/0x40 Apr 16 22:40:37 barnabas kernel: [19055.486716] [<ffffffff81183b12>] ? fput+0x1a2/0x260 Apr 16 22:40:37 barnabas kernel: [19055.486723] [<ffffffff811948d9>] sys_ioctl+0x99/0xa0 Apr 16 22:40:37 barnabas kernel: [19055.486733] [<ffffffff81689a69>] system_call_fastpath+0x16/0x1b Apr 16 22:40:37 barnabas kernel: [19055.486787] INFO: task kworker/2:0:4122 blocked for more than 120 seconds. Apr 16 22:40:37 barnabas kernel: [19055.486808] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Apr 16 22:40:37 barnabas kernel: [19055.486812] kworker/2:0 D ffff88023f2939c0 0 4122 2 0x00000000 Apr 16 22:40:37 barnabas kernel: [19055.486819] ffff88019004dcf0 0000000000000046 ffff880232a59700 ffff88019004dfd8 Apr 16 22:40:37 barnabas kernel: [19055.486827] ffff88019004dfd8 ffff88019004dfd8 ffff8802343a4500 ffff880232a59700 Apr 16 22:40:37 barnabas kernel: [19055.486833] ffff88019004dce0 ffff88022ec253a0 ffff880232a59700 ffff88022ec253a4 Apr 16 22:40:37 barnabas kernel: [19055.486840] Call Trace: Apr 16 22:40:37 barnabas kernel: [19055.486852] [<ffffffff816808b9>] schedule+0x29/0x70 Apr 16 22:40:37 barnabas kernel: [19055.486863] [<ffffffff81680b7e>] schedule_preempt_disabled+0xe/0x10 Apr 16 22:40:37 barnabas kernel: [19055.486872] [<ffffffff8167f697>] __mutex_lock_slowpath+0xd7/0x150 Apr 16 22:40:37 barnabas kernel: [19055.486881] [<ffffffff8167f16a>] mutex_lock+0x2a/Apr 16 22:41:08 barnabas kernel: imklog 5.8.6, log source = /proc/kmsg started. --- -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/926637 Title: Xorg crashes to black screen when attaching HDMI Samsung monitor to laptop To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-nouveau/+bug/926637/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs