Public bug reported:
When systems run with the `nosmt` flag set in the kernel cmdline, SMT siblings
never come online. The ACPI CPPC library only initializes online CPUs.
nvidia@localhost:/home/nvidia/acpi$ ll -d
/sys/devices/system/cpu/cpu*/acpi_cppc/ | wc -l
88
nvidia@localhost:/home/nvidia/acpi$ ll -d /sys/devices/system/cpu/cpu*// | wc -l
178
Then cppc_cpufreq initialization calls `acpi_cpc_valid`, which checks the
tables for all present CPUs.
bool acpi_cpc_valid(void)
{
struct cpc_desc *cpc_ptr;
int cpu;
if (acpi_disabled)
return false;
for_each_present_cpu(cpu) {
cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
if (!cpc_ptr)
return false;
}
return true;
}
EXPORT_SYMBOL_GPL(acpi_cpc_valid);
Because the offline cores are still present, `acpi_cpc_valid` will fail.
Backport fixes for this from:
1) https://lore.kernel.org/all/[email protected]/ (4
of the 5 patches from this series are already present, take the amd-pstate one
to be complete)
2) https://lore.kernel.org/all/[email protected]/
** Affects: linux-nvidia-6.17 (Ubuntu)
Importance: Undecided
Status: New
** Package changed: linux-nvidia-6.14 (Ubuntu) => linux-nvidia-6.17
(Ubuntu)
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https://bugs.launchpad.net/bugs/2141613
Title:
backport CPPC fixes for "nosmt"/"nosmt=force" scenarios
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