3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lan Tianyu <tianyu.lan@xxxxxxxxx> commit 4985c32ee4241d1aba1beeac72294faa46aaff10 upstream. 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. Fixes: b981513f806d (ACPI / scan: bail out early if failed to parse APIC ID for CPU) References: https://bugzilla.kernel.org/show_bug.cgi?id=73781 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> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/acpi/acpi_processor.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -170,6 +170,9 @@ static int acpi_processor_hotadd_init(st acpi_status status; int ret; + if (pr->apic_id == -1) + return -ENODEV; + status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta); if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT)) return -ENODEV; @@ -260,10 +263,8 @@ static int acpi_processor_get_info(struc } 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); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html