The below issue is occasionally seen during running suspend/resume with preemp-rt kernel. You will see in the below text, the timeframe where the board was awakened from sleep. The highlighted text is what they are concerned about. Freezing user space processes ... (elapsed 0.01 seconds) done. Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done. Suspending console(s) (use no_console_suspend to debug) ACPI handle has no context! pch_gpio 0000:02:00.2: pci_enable_wake Failed --22 tty ttyS0: parent serial8250 should not be sleeping tty ttyS1: parent serial8250 should not be sleeping Watchdog exit sdhci-pci 0000:02:04.1: setting latency timer to 64 PM: suspend of devices complete after 183.079 msecs PM: late suspend of devices complete after 0.294 msecs ehci_hcd 0000:02:08.3: wake-up capability enabled by ACPI ohci_hcd 0000:02:08.2: wake-up capability enabled by ACPI ohci_hcd 0000:02:08.1: wake-up capability enabled by ACPI ohci_hcd 0000:02:08.0: wake-up capability enabled by ACPI ehci_hcd 0000:02:02.3: wake-up capability enabled by ACPI ohci_hcd 0000:02:02.2: wake-up capability enabled by ACPI ohci_hcd 0000:02:02.1: wake-up capability enabled by ACPI ohci_hcd 0000:02:02.0: wake-up capability enabled by ACPI pch_gbe 0000:02:00.1: wake-up capability enabled by ACPI PM: noirq suspend of devices complete after 144.078 msecs ACPI: Preparing to enter system sleep state S3 PM: Saving platform NVS memory Disabling non-boot CPUs ... BUG: using smp_processor_id() in preemptible [00000000 00000000] code: ksoftirqd/1/12 caller is do_current_softirqs+0x9d/0x2f0 Pid: 12, comm: ksoftirqd/1 Tainted: G W O 3.4.88-rt56-WR5.0.1.17_preempt-rt #1 Call Trace: [<c131a951>] debug_smp_processor_id+0xf1/0x110 [<c10369bd>] do_current_softirqs+0x9d/0x2f0 [<c175007b>] ? elf_map+0xbe/0xe8 [<c10300d8>] ? panic_smp_self_stop+0x8/0x20 [<c1036cf3>] run_ksoftirqd+0xe3/0x1b0 [<c1036c10>] ? do_current_softirqs+0x2f0/0x2f0 [<c104f3ae>] kthread+0x6e/0x80 [<c104f340>] ? __init_kthread_worker+0x40/0x40 [<c175ed3a>] kernel_thread_helper+0x6/0x10 CPU 1 is now offline ACPI: Low-level resume complete PM: Restoring platform NVS memory Enabling non-boot CPUs ... Booting Node 0 Processor 1 APIC 0x1 Initializing CPU#1 checking TSC synchronization [CPU#0 -> CPU#1]: passed. NMI watchdog: disabled (cpu1): unable to create perf event: -13 CPU1 is up ACPI: Waking up from system sleep state S3 Customer's hardware is based on Eurotech Catalyst TC, which is very similar to the intel_atom_eg20t_pch and somewhat similar to the intel_atom_z530 target/bsp .
