I am running Ubuntu 16.04 LTS on a Dell XPS 15 9550 (16 GB RAM, FHD screen, 512 GB SSD, Intel i7-6700HQ). It is dual booted with Windows, for which I followed the instructions in this thread.
Almost everything works very well. However, when I suspend either by closing the lid, or using
systemctl suspend sometimes (about 50% of the time) Ubuntu doesn't suspend. The screen goes dark as if it is about to suspend, but then it flashes back directly to the login screen.
I believe the issue must be related to my Broadcom wifi card/driver. The output of dmesg during a failed suspend is:
[36482.669029] PM: Syncing filesystems ... done. [36482.697429] PM: Preparing system for sleep (mem) [36482.698220] vgaarb: this pci device is not a vga device [36483.937858] Freezing user space processes ... (elapsed 0.002 seconds) done. [36483.940227] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. [36483.941564] PM: Suspending system (mem) [36483.941623] Suspending console(s) (use no_console_suspend to debug) [36487.637784] brcmf_pcie_suspend: Timeout on response for entering D3 substate [36487.637802] pci_legacy_suspend(): brcmf_pcie_suspend+0x0/0x1b0 [brcmfmac] returns -5 [36487.637808] dpm_run_callback(): pci_pm_suspend+0x0/0x140 returns -5 [36487.637813] PM: Device 0000:02:00.0 failed to suspend async: error -5 [36487.637902] PM: Some devices failed to suspend, or early wake event detected [36487.641932] rtc_cmos 00:02: System wakeup disabled by ACPI [36488.017866] ata2: SATA link down (SStatus 4 SControl 300) [36488.149475] PM: resume of devices complete after 511.560 msecs [36488.158754] PM: Finishing wakeup.
There is also the message
brcmfmac 0000:02:00.0: Direct firmware load for brcm/brcmfmac43602-pcie.txt failed with error -2
whenever I boot or resume from a [successful] suspend. Also to note: when suspend fails, my wifi stops working (I believe it says "no device"). The only ways to get it to work again are to either reboot, or:
sudo rmmod brcmfmac sudo modprobe brcmfmac
Here is the output of a wifi info script. Any help at all would be very much appreciated! Thank you in advance, and let me know if any more information would be helpful.
EDIT: Issue has returned after upgrade to 18.04. The previously accepted answer no longer seems to work because
systemd does not unload modules from suggested file before suspending.