On 21 February 2023 09:49:51 GMT, Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx> wrote: >On 21.02.2023 10:06, David Woodhouse wrote: >> Why does arch/x86/kernel/acpi/sleep.c::x86_acpi_suspend_lowlevel() set >> >> initial_gs = per_cpu_offset(smp_processor_id()) ? >> >> Would it not be CPU#0 that comes back up, and should it not get >> per_cpu_offset(0) ? > >Wanna me try `initial_gs = per_cpu_offset(0);` too? Hm, yes please. There's another one to make zero on the next line up, I think? >> Or maybe we should just set up smpboot_control for the CPU to find its >> own stuff, *even* on waking. Since the structures are already set up, >> it isn't like a clean boot. >> >> If you let it boot in parallel mode, what if you just *remove* the line >> that sets smpboot_control=0 ? > >If the `smpboot_control = 0;` line in arch/x86/kernel/acpi/sleep.c::x86_acpi_suspend_lowlevel() is commented out, and the system is booted in parallel mode, then suspend/resume works. Well that's entertaining. Now, can we come up with any theory which doesn't leave us wondering why it ever worked in the first place...?
