Thread (19 messages) 19 messages, 3 authors, 2021-12-23
STALE1628d
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[PATCH v6 04/14] ACPI: CPPC: Check present CPUs for determining _CPC is valid

From: Huang Rui <ray.huang@amd.com>
Date: 2021-12-19 16:36:24
Also in: lkml
Subsystem: acpi, the rest · Maintainers: "Rafael J. Wysocki", Linus Torvalds

From: Mario Limonciello <mario.limonciello@amd.com>

As this is a static check, it should be based upon what is currently
present on the system. This makes probeing more deterministic.

While local APIC flags field (lapic_flags) of cpu core in MADT table is
0, then the cpu core won't be enabled. In this case, _CPC won't be found
in this core, and return back to _CPC invalid with walking through
possible cpus (include disable cpus). This is not expected, so switch to
check present CPUs instead.

Reported-by: Jinzhou Su <redacted>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
---
 drivers/acpi/cppc_acpi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index df2933c28bec..0c4f7005818e 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -413,7 +413,7 @@ bool acpi_cpc_valid(void)
 	struct cpc_desc *cpc_ptr;
 	int cpu;
 
-	for_each_possible_cpu(cpu) {
+	for_each_present_cpu(cpu) {
 		cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 		if (!cpc_ptr)
 			return false;
-- 
2.25.1
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