From 856b185dd23da39e562983fbf28860f54e661b41 Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Thu, 17 Jun 2010 09:08:54 -0600 Subject: [PATCH] ACPI: processor: fix processor_physically_present on UP The commit 5d554a7bb06 (ACPI: processor: add internal processor_physically_present()) is broken on uniprocessor (UP) configurations, as acpi_get_cpuid() will always return -1. We use the value of num_possible_cpus() to tell us whether we got an invalid cpuid from acpi_get_cpuid() in the SMP case, or if instead, we are UP, in which case num_possible_cpus() is #defined as 1. We use num_possible_cpus() instead of num_online_cpus() to protect ourselves against the scenario of CPU hotplug, and we've taken down all the CPUs except one. Thanks to Jan Pogadl for initial report and analysis and Chen Gong for review. https://bugzilla.kernel.org/show_bug.cgi?id=16357 Reported-by: Jan Pogadl : Reviewed-by: Chen Gong Signed-off-by: Alex Chiang Signed-off-by: Len Brown --- drivers/acpi/processor_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c index 51284351418f..e9699aaed109 100644 --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c @@ -223,7 +223,7 @@ static bool processor_physically_present(acpi_handle handle) type = (acpi_type == ACPI_TYPE_DEVICE) ? 1 : 0; cpuid = acpi_get_cpuid(handle, type, acpi_id); - if (cpuid == -1) + if ((cpuid == -1) && (num_possible_cpus() > 1)) return false; return true;