On 21/02/2023 10:27, David Woodhouse wrote:
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?
I think it might be smp_processor_id() and not 0 incase CPU0 was offline
at the point the system was suspended?
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...?
