[PATCH] ACPI/Processor: Fix failure of loading acpi-cpufreq driver

[Lan Tianyu]

According commit d640113fe(ACPI: processor: fix acpi_get_cpuid for UP
processor),  Bios may not provide _MAT or MADT tables and acpi_get_apicid()
always returns -1. For these cases, original code will pass apic_id with
vaule of -1 to acpi_map_cpuid() and it will check the acpi_id. If acpi_id
is equal to zero, ignores apic_id and return zero for CPU0.

Commit b981513(ACPI / scan: bail out early if failed to parse APIC
ID for CPU) changed the behavior. Return ENODEV when find apic_id is
less than zero after calling acpi_get_apicid(). This causes acpi-cpufreq
driver fails to be loaded on some machines. This patch is to fix it.

Reference:https://bugzilla.kernel.org/show_bug.cgi?id=73781
Cc: stable@xxxxxxxxxxxxxxx v3.14
Reported-and-tested-by: KATO Hiroshi <katoh@xxxxxxxxxxxx>
Reported-and-tested-by: Stuart Foster <smf.linux@xxxxxxxxxxxx>
Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
---
 drivers/acpi/acpi_processor.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index c29c2c3..d55b603 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -260,10 +260,8 @@ static int acpi_processor_get_info(struct acpi_device *device)
 	}
 
 	apic_id = acpi_get_apicid(pr->handle, device_declaration, pr->acpi_id);
-	if (apic_id < 0) {
+	if (apic_id < 0)
 		acpi_handle_debug(pr->handle, "failed to get CPU APIC ID.\n");
-		return -ENODEV;
-	}
 	pr->apic_id = apic_id;
 
 	cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
-- 
1.8.4.rc0.1.g8f6a3e5.dirty

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