See also https://bugs.freedesktop.org/show_bug.cgi?id=106447 and https://bugzilla.kernel.org/show_bug.cgi?id=199609

-----

The system immediately locks up when resuming from suspend. I get to see the mouse cursor and the blue background of KDE's screen lock (but no password entry or anything like that), but cannot do anything.

I can also reproduce on 4.16.7 and 4.17-rc4. This does not happen with amdgpu blacklisted, or with Arch Linux' LTS kernel (4.14.39) though I get other random failures on the LTS kernel.

Unfortunately, the systemd journal does not contain anything after entering suspend so I have no possibility to get at a backtrace.

-----

I did a bisect and git reported this as the culprit:

kugel@thomas-nb:linux.git$ git bisect good
08810a4119aaebf6318f209ec5dd9828e969cba4 is the first bad commit
commit 08810a4119aaebf6318f209ec5dd9828e969cba4
Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date:   Wed Oct 25 14:12:29 2017 +0200

    PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags
    
    The motivation for this change is to provide a way to work around
    a problem with the direct-complete mechanism used for avoiding
    system suspend/resume handling for devices in runtime suspend.
    
    The problem is that some middle layer code (the PCI bus type and
    the ACPI PM domain in particular) returns positive values from its
    system suspend ->prepare callbacks regardless of whether the driver's
    ->prepare returns a positive value or 0, which effectively prevents
    drivers from being able to control the direct-complete feature.
    Some drivers need that control, however, and the PCI bus type has
    grown its own flag to deal with this issue, but since it is not
    limited to PCI, it is better to address it by adding driver flags at
    the core level.
    
    To that end, add a driver_flags field to struct dev_pm_info for flags
    that can be set by device drivers at the probe time to inform the PM
    core and/or bus types, PM domains and so on on the capabilities and/or
    preferences of device drivers.  Also add two static inline helpers
    for setting that field and testing it against a given set of flags
    and make the driver core clear it automatically on driver remove
    and probe failures.
    
    Define and document two PM driver flags related to the direct-
    complete feature: NEVER_SKIP and SMART_PREPARE that can be used,
    respectively, to indicate to the PM core that the direct-complete
    mechanism should never be used for the device and to inform the
    middle layer code (bus types, PM domains etc) that it can only
    request the PM core to use the direct-complete mechanism for
    the device (by returning a positive value from its ->prepare
    callback) if it also has been requested by the driver.
    
    While at it, make the core check pm_runtime_suspended() when
    setting power.direct_complete so that it doesn't need to be
    checked by ->prepare callbacks.
    
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Acked-by: Bjorn Helgaas <bhelgaas@google.com>
    Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

:040000 040000 6f18a781ca7ee0501888a66532f0667f2926aeb1 440821a72777285dccc37d3a8254688bf4a24486 M      Documentation
:040000 040000 6aaceba7f5aae9368a1e6e287a1f56cb1326adbf 557c1672f5101aeae16ce6bda4969c42dd3321bb M      drivers
:040000 040000 bdc707f2a476baf517361c46ed28977cb30b6e1b 7c33fb89c953ad06a7b1c8b686d6b6a403aa509b M      include

Interestingly, this commit seems to also affect my wifi. I.e. the good commits (from the susped pov) do not have working wifi, while bad commits have working wifi.

I investigated the commit a bit more, and found that the following patch (which reverts part of said commit) repairs resuming.

I can't tell the consequences, however reading the commit message suggests this part is non-critical:

> While at it, make the core check pm_runtime_suspended() when
> setting power.direct_complete so that it doesn't need to be
> checked by ->prepare callbacks.

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 02a497e7c785..028c14386e5d 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1959,9 +1959,7 @@ static int device_prepare(struct device *dev, pm_message_t state)
         * applies to suspend transitions, however.
         */
        spin_lock_irq(&dev->power.lock);
-       dev->power.direct_complete = state.event == PM_EVENT_SUSPEND &&
-               pm_runtime_suspended(dev) && ret > 0 &&
-               !dev_pm_test_driver_flags(dev, DPM_FLAG_NEVER_SKIP);
+       dev->power.direct_complete = ret > 0 && state.event == PM_EVENT_SUSPEND;
        spin_unlock_irq(&dev->power.lock);
        return 0;
 }

-----


System:
Arch Linux w/ Linux 4.16.7
DMI: HP ZBook 14u G5/83B2, BIOS Q78 Ver. 01.00.05 01/25/2018
Intel Kaby Refresh 8550u
Intel UHD 620
AMD Radeon PRO WX 3100 (I believe this is Polaris, not sure about exact Generation)

lspci:
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v6/7th Gen Core Processor Host Bridge/DRAM Registers (rev 08)
00:02.0 VGA compatible controller: Intel Corporation UHD Graphics 620 (rev 07)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 08)
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21)
00:15.0 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #0 (rev 21)
00:15.1 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #1 (rev 21)
00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI #1 (rev 21)
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #1 (rev f1)
00:1c.3 PCI bridge: Intel Corporation Device 9d13 (rev f1)
00:1c.4 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #5 (rev f1)
00:1d.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #9 (rev f1)
00:1f.0 ISA bridge: Intel Corporation Device 9d4e (rev 21)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21)
00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev 21)
00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21)
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (4) I219-V (rev 21)
01:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Lexa XT [Radeon PRO WX 3100]
02:00.0 Network controller: Intel Corporation Wireless 8265 / 8275 (rev 78)
3c:00.0 Non-Volatile memory controller: Toshiba America Info Systems Device 0116