Hi, I updated the Linux kernel on an old machine from v6.5.9 to current v6.8.8 and found the display failed after resume from suspend to RAM. Then I tried v6.7.9 and v6.6.29, both also failed. v6.5.9 works. - display connected via display port: hangup - I also tried HDMI with v6.6.29: garbage (color noise) after wakeup, after a bit of switching between Linux virtual consoles the display came back to live, first flickering between color noise and actual output, then stable output CPU/GPU: Core i5-3550 00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09) 00:02.0 0300: 8086:0152 (rev 09) HDMI generates this error in kernel log: [ C0] i915 0000:00:02.0: [drm] *ERROR* uncleared pch fifo underrun on pch transcoder A [ C0] i915 0000:00:02.0: [drm] *ERROR* PCH transcoder A FIFO underrun DP genrates this error spew on v6.6.29: [ C3] i915 0000:00:02.0: [drm] *ERROR* uncleared pch fifo underrun on pch transcoder A [ C3] i915 0000:00:02.0: [drm] *ERROR* PCH transcoder A FIFO underrun [ T3502] PM: suspend entry (deep) ... [ T3927] ------------[ cut here ]------------ [ T3927] i915 0000:00:02.0: drm_WARN_ON((intel_de_read(dev_priv, intel_dp->output_reg) & (1 << 31)) == 0) [ T3927] WARNING: CPU: 2 PID: 3927 at drivers/gpu/drm/i915/display/g4x_dp.c:417 intel_dp_link_down.isra.0+0x2e4/0x300 [ T3927] Modules linked in: mt76x0u mt76x0_common mt76x02_usb mt76_usb mt76x02_lib mt76 mac80211 kvm_intel cfg80211 kv> [ T3927] CPU: 2 PID: 3927 Comm: kworker/u8:26 Not tainted 6.6.29 #1 [ T3927] Hardware name: System manufacturer System Product Name/P8H77-V, BIOS 1905 10/27/2014 [ T3927] Workqueue: events_unbound async_run_entry_fn [ T3927] RIP: 0010:intel_dp_link_down.isra.0+0x2e4/0x300 [ T3927] Code: 48 8b 5f 50 48 85 db 75 03 48 8b 1f e8 c5 0d 07 00 48 c7 c1 70 8c ac 89 48 89 da 48 c7 c7 f1 16 9d 89 4> [ T3927] RSP: 0018:ffffa41d41b37a68 EFLAGS: 00010246 [ T3927] RAX: 0000000000000000 RBX: ffff9df340d79380 RCX: 0000000000000000 [ T3927] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ T3927] RBP: ffff9df346478000 R08: 0000000000000000 R09: 0000000000000000 [ T3927] R10: 0000000000000000 R11: 0000000000000000 R12: ffff9df34647ad68 [ T3927] R13: ffff9df34649e000 R14: 0000000000000001 R15: 0000000000000000 [ T3927] FS: 0000000000000000(0000) GS:ffff9df64f800000(0000) knlGS:0000000000000000 [ T3927] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ T3927] CR2: 00007f026e63418c CR3: 000000032bc50006 CR4: 00000000001706e0 [ T3927] Call Trace: [ T3927] <TASK> [ T3927] ? __warn+0x80/0x160 [ T3927] ? intel_dp_link_down.isra.0+0x2e4/0x300 [ T3927] ? report_bug+0x19e/0x1d0 [ T3927] ? handle_bug+0x40/0x80 [ T3927] ? exc_invalid_op+0x13/0x70 [ T3927] ? asm_exc_invalid_op+0x16/0x20 [ T3927] ? intel_dp_link_down.isra.0+0x2e4/0x300 [ T3927] ? intel_dp_link_down.isra.0+0x2e4/0x300 [ T3927] g4x_post_disable_dp+0x2e/0x120 [ T3927] intel_encoders_post_disable+0x72/0x90 [ T3927] ilk_crtc_disable+0x80/0xe0 [ T3927] intel_atomic_commit_tail+0x404/0xed0 [ T3927] ? intel_atomic_commit+0x374/0x3c0 [ T3927] ? intel_atomic_commit+0x30a/0x3c0 [ T3927] intel_atomic_commit+0x374/0x3c0 [ T3927] drm_atomic_commit+0x96/0xd0 [ T3927] ? __pfx___drm_printfn_info+0x10/0x10 [ T3927] drm_atomic_helper_disable_all+0x19a/0x1b0 [ T3927] drm_atomic_helper_suspend+0xd5/0x240 [ T3927] intel_display_driver_suspend+0x28/0x70 [ T3927] i915_drm_suspend+0x42/0xf0 [ T3927] pci_pm_suspend+0x73/0x170 [ T3927] ? __pfx_pci_pm_suspend+0x10/0x10 [ T3927] dpm_run_callback+0x52/0x190 [ T3927] __device_suspend+0xf3/0x4b0 [ T3927] ? process_one_work+0x1ad/0x510 [ T3927] async_suspend+0x1a/0x60 [ T3927] async_run_entry_fn+0x30/0x160 [ T3927] ? process_one_work+0x1ad/0x510 [ T3927] process_one_work+0x219/0x510 [ T3927] worker_thread+0x1d6/0x3e0 [ T3927] ? __pfx_worker_thread+0x10/0x10 [ T3927] kthread+0xf6/0x130 [ T3927] ? __pfx_kthread+0x10/0x10 [ T3927] ret_from_fork+0x30/0x50 [ T3927] ? __pfx_kthread+0x10/0x10 [ T3927] ret_from_fork_asm+0x1b/0x30 [ T3927] </TASK> [ T3927] ---[ end trace 0000000000000000 ]--- [ T3502] ACPI: PM: Preparing to enter system sleep state S3 [ T3502] ACPI: PM: Saving platform NVS memory [ T3502] Disabling non-boot CPUs ... ... [ T3502] ACPI: PM: Waking up from system sleep state S3 [ T3928] i915 0000:00:02.0: vgaarb: VGA decodes changed: olddecodes=io+mem,decodes=io+mem:owns=io+mem [ T3502] PM: suspend exit [ C0] i915 0000:00:02.0: [drm] *ERROR* uncleared pch fifo underrun on pch transcoder A [ C0] i915 0000:00:02.0: [drm] *ERROR* PCH transcoder A FIFO underrun [ C0] sysrq: Emergency Sync [ T8] Emergency Sync complete [ C0] sysrq: Emergency Remount R/O and on v6.8.8: [ C3] i915 0000:00:02.0: [drm] *ERROR* uncleared pch fifo underrun on pch transcoder A [ C3] i915 0000:00:02.0: [drm] *ERROR* PCH transcoder A FIFO underrun [T10083] PM: suspend entry (deep) ... [T10083] ACPI: PM: Waking up from system sleep state S3 [T10083] serial 00:06: activated [T10569] i915 0000:00:02.0: vgaarb: VGA decodes changed: olddecodes=io+mem,decodes=io+mem:owns=io+mem ... [T10083] PM: suspend exit [ C0] i915 0000:00:02.0: [drm] *ERROR* uncleared pch fifo underrun on pch transcoder A [ C0] i915 0000:00:02.0: [drm] *ERROR* PCH transcoder A FIFO underrun ... [ T37] INFO: task kworker/1:1:47 blocked for more than 122 seconds. [ T37] Not tainted 6.8.8 #1 [ T37] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ T37] task:kworker/1:1 state:D stack:0 pid:47 tgid:47 ppid:2 flags:0x00004000 [ T37] Workqueue: i915-unordered i915_hotplug_work_func [ T37] Call Trace: [ T37] <TASK> [ T37] __schedule+0x4c9/0x1810 [ T37] ? find_held_lock+0x2b/0x90 [ T37] ? find_held_lock+0x2b/0x90 [ T37] schedule+0x49/0x150 [ T37] schedule_preempt_disabled+0x18/0x30 [ T37] __ww_mutex_lock.constprop.0+0x90e/0x12d0 [ T37] ? modeset_lock+0x17d/0x1e0 [ T37] ? modeset_lock+0x17d/0x1e0 [ T37] modeset_lock+0x17d/0x1e0 [ T37] drm_helper_probe_detect_ctx+0x7b/0x120 [ T37] intel_hotplug_detect_connector+0x43/0x120 [ T37] intel_hdmi_hotplug+0xe/0x30 [ T37] i915_hotplug_work_func+0x2af/0x3e0 [ T37] ? process_one_work+0x1ad/0x510 [ T37] process_one_work+0x219/0x510 [ T37] worker_thread+0x1d6/0x3e0 [ T37] ? __pfx_worker_thread+0x10/0x10 [ T37] kthread+0xf6/0x130 [ T37] ? __pfx_kthread+0x10/0x10 [ T37] ret_from_fork+0x30/0x50 [ T37] ? __pfx_kthread+0x10/0x10 [ T37] ret_from_fork_asm+0x1b/0x30 [ T37] </TASK> [ T37] INFO: task Xorg:3197 blocked for more than 122 seconds. [ T37] Not tainted 6.8.8 #1 [ T37] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ T37] task:Xorg state:D stack:0 pid:3197 tgid:3197 ppid:3185 flags:0x00400002 [ T37] Call Trace: [ T37] <TASK> [ T37] __schedule+0x4c9/0x1810 [ T37] ? find_held_lock+0x2b/0x90 [ T37] schedule+0x49/0x150 [ T37] drm_vblank_work_flush+0x92/0xf0 [ T37] ? __pfx_autoremove_wake_function+0x10/0x10 [ T37] intel_wait_for_vblank_workers+0x4b/0x90 [ T37] intel_atomic_commit_tail+0x747/0x1080 [ T37] ? find_held_lock+0x2b/0x90 [ T37] ? local_clock_noinstr+0x9/0xc0 [ T37] ? _raw_spin_unlock+0x29/0x60 [ T37] ? intel_atomic_commit+0x2f3/0x340 [ T37] ? intel_atomic_commit+0x299/0x340 [ T37] intel_atomic_commit+0x2f3/0x340 [ T37] drm_atomic_commit+0x96/0xd0 [ T37] ? __pfx___drm_printfn_info+0x10/0x10 [ T37] drm_mode_gamma_set_ioctl+0x3c5/0x590 [ T37] ? __pfx_drm_mode_gamma_set_ioctl+0x10/0x10 [ T37] drm_ioctl_kernel+0xbc/0x110 [ T37] drm_ioctl+0x284/0x500 [ T37] ? __pfx_drm_mode_gamma_set_ioctl+0x10/0x10 [ T37] __x64_sys_ioctl+0xa9/0xd0 [ T37] do_syscall_64+0x7b/0x140 [ T37] ? local_clock_noinstr+0x9/0xc0 [ T37] ? lock_release+0x14a/0x400 [ T37] ? trace_hardirqs_on_prepare+0x3c/0xb0 [ T37] ? syscall_exit_to_user_mode+0x9c/0x1a0 [ T37] ? do_syscall_64+0x87/0x140 [ T37] ? do_syscall_64+0x87/0x140 [ T37] ? do_syscall_64+0x87/0x140 [ T37] ? trace_hardirqs_on_prepare+0x3c/0xb0 [ T37] entry_SYSCALL_64_after_hwframe+0x78/0x80 [ T37] RIP: 0033:0x7f0a152195cb [ T37] RSP: 002b:00007ffe12bd6410 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ T37] RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00007f0a152195cb [ T37] RDX: 00007ffe12bd64a0 RSI: 00000000c02064a5 RDI: 000000000000000f [ T37] RBP: 00007ffe12bd64a0 R08: 0000564b17a70950 R09: 0000564b17a70b50 [ T37] R10: 0000564b17a70750 R11: 0000000000000246 R12: 00000000c02064a5 [ T37] R13: 000000000000000f R14: 0000000000000003 R15: 00007ffe12bd6560 [ T37] </TASK> [ T37] [ T37] Showing all locks held in the system: [ T37] 1 lock held by khungtaskd/37: [ T37] #0: ffffffff87d601c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x32/0x110 [ T37] 6 locks held by kworker/1:1/47: [ T37] #0: ffff927000c09548 ((wq_completion)i915-unordered){....}-{0:0}, at: process_one_work+0x1ad/0x510 [ T37] #1: ffffb1d6801bbe50 ((work_completion)(&(&i915->display.hotplug.hotplug_work)->work)){....}-{0:0}, at: proc> [ T37] #2: ffff9270074084f0 (&dev->mode_config.mutex){....}-{3:3}, at: i915_hotplug_work_func+0x58/0x3e0 [ T37] #3: ffffffff87e4d680 (drm_connector_list_iter){....}-{0:0}, at: i915_hotplug_work_func+0x1fc/0x3e0 [ T37] #4: ffffb1d6801bbce0 (crtc_ww_class_acquire){....}-{0:0}, at: drm_helper_probe_detect_ctx+0x4b/0x120 [ T37] #5: ffff927007408590 (crtc_ww_class_mutex){....}-{3:3}, at: modeset_lock+0x17d/0x1e0 [ T37] 1 lock held by in:imklog/2976: [ T37] #0: ffff9270012698d8 (&f->f_pos_lock){....}-{3:3}, at: __fdget_pos+0x52/0x80 [ T37] 2 locks held by Xorg/3197: [ T37] #0: ffffb1d682027bf8 (crtc_ww_class_acquire){....}-{0:0}, at: drm_mode_gamma_set_ioctl+0x15d/0x590 [ T37] #1: ffff927007408590 (crtc_ww_class_mutex){....}-{3:3}, at: modeset_lock+0x17d/0x1e0 [ T37] 2 locks held by kworker/u8:61/10605: [ T37] #0: ffff9270001da748 ((wq_completion)phy2){....}-{0:0}, at: process_one_work+0x1ad/0x510 [ T37] #1: ffffb1d68213fe50 ((work_completion)(&(&dev->cal_work)->work)){....}-{0:0}, at: process_one_work+0x1ad/0x> [ T37] [ T37] ============================================= I hope you have ideas about fixes to try, bisect testing takes much time which I don't have... Best Regards, Johannes