On 1 February 2018 at 01:42, Peter Hutterer <peter.hutterer@who-t.net> wrote:

[..] 

> So event4 it is in my case touch pad and event5  it is Logitech M185 mouse.
> In other words: those "libinput bug" log entries looks like are not related
> to emitting those short bursts of repeating keystrokes.

not directly, but they indicate where the issue is: key repeat is handled in
the clients, not in libinput. With delays like this it's easy to see why you
would get key repeat - if your key release event is delayed by 300ms or more
the client will handle repeats before it gets the events.

But the real cause of the issue is that you're getting crazy delays because
gnome-shell is too busy with something else. The rest is fallout from that.

So that is quite possible explanation and cause of those delays probably is in what I've already described.

Every few second in kernel messages I have sequence:

[74330.405990] [drm] PCIE gen 2 link speeds already enabled

[74330.417096] [drm] PCIE GART of 1024M enabled (table at 0x0000000000162000).

[74330.417206] radeon 0000:01:00.0: WB enabled

[74330.417212] radeon 0000:01:00.0: fence driver on ring 0 use gpu addr 0x0000000020000c00 and cpu addr 0x00000000d8c75981

[74330.417216] radeon 0000:01:00.0: fence driver on ring 3 use gpu addr 0x0000000020000c0c and cpu addr 0x000000001142ed24

[74330.417965] radeon 0000:01:00.0: fence driver on ring 5 use gpu addr 0x0000000000072118 and cpu addr 0x00000000095357f2

[74330.434413] [drm] ring test on 0 succeeded in 2 usecs

[74330.434428] [drm] ring test on 3 succeeded in 7 usecs

[74330.611793] [drm] ring test on 5 succeeded in 2 usecs

[74330.611809] [drm] UVD initialized successfully.

[74330.611949] [drm] ib test on ring 0 succeeded in 0 usecs

[74330.612118] [drm] ib test on ring 3 succeeded in 0 usecs

[74331.267267] [drm] ib test on ring 5 succeeded

[74340.515810] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes)

[74340.515819] swiotlb: coherent allocation failed for device 0000:01:00.0 size=2097152

[74340.515827] CPU: 0 PID: 27342 Comm: kworker/0:1 Tainted: G        W        4.15.0-0.rc9.git4.1.fc28.x86_64 #1

[74340.515832] Hardware name: Sony Corporation VPCSB2M9E/VAIO, BIOS R2087H4 06/15/2012

[74340.515841] Workqueue: pm pm_runtime_work

[74340.515849] Call Trace:

[74340.515862]  dump_stack+0x85/0xbf

[74340.515871]  swiotlb_alloc_coherent+0xe0/0x150

[74340.515889]  ttm_dma_pool_get_pages+0x21b/0x620 [ttm]

[74340.515908]  ttm_dma_populate+0x24d/0x340 [ttm]

[74340.515923]  ttm_bo_move_memcpy+0x185/0x610 [ttm]

[74340.515933]  ? lock_acquire+0x9f/0x200

[74340.515940]  ? reservation_object_wait_timeout_rcu+0xb3/0x500

[74340.515987]  radeon_bo_move+0x1a7/0x220 [radeon]

[74340.516003]  ttm_bo_handle_move_mem+0x2a4/0x5d0 [ttm]

[74340.516021]  ttm_bo_evict+0x186/0x370 [ttm]

[74340.516046]  ttm_mem_evict_first+0x174/0x1d0 [ttm]

[74340.516060]  ttm_bo_force_list_clean+0x6d/0x130 [ttm]

[74340.516089]  radeon_suspend_kms+0x11e/0x3e0 [radeon]

[74340.516103]  ? vga_switcheroo_runtime_resume+0x60/0x60

[74340.516126]  radeon_pmops_runtime_suspend+0x54/0xc0 [radeon]

[74340.516135]  pci_pm_runtime_suspend+0x61/0x170

[74340.516144]  vga_switcheroo_runtime_suspend+0x24/0xa0

[74340.516151]  __rpm_callback+0xbc/0x1f0

[74340.516160]  ? vga_switcheroo_runtime_resume+0x60/0x60

[74340.516168]  rpm_callback+0x1f/0x70

[74340.516175]  ? vga_switcheroo_runtime_resume+0x60/0x60

[74340.516181]  rpm_suspend+0x12d/0x6e0

[74340.516195]  pm_runtime_work+0x73/0xb0

[74340.516204]  process_one_work+0x249/0x6b0

[74340.516219]  worker_thread+0x3a/0x390

[74340.516229]  ? process_one_work+0x6b0/0x6b0

[74340.516236]  kthread+0x121/0x140

[74340.516243]  ? kthread_create_worker_on_cpu+0x70/0x70

[74340.516253]  ret_from_fork+0x3a/0x50

during which whole desktop is frozen for fraction of the second. During those freezes it is not possible even to move mouse cursor.

Do you have idea what it may be?