ACPI: Fix regression where _PPC is not read at boot even when ignore_ppc=0

Earlier, Ingo Molnar posted a patch to make it so that the kernel would avoid
reading _PPC on his broken T60.  Unfortunately, it seems that with Thomas
Renninger's patch last July to eliminate _PPC evaluations when the processor
driver loads, the kernel never actually reads _PPC at all!  This is problematic
if you happen to boot your non-T60 computer in a state where the BIOS _wants_
_PPC to be something other than zero.

So, put the _PPC evaluation back into acpi_processor_get_performance_info if
ignore_ppc isn't 1.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index 2cabadcc4d8c..a959f6a07508 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -413,7 +413,11 @@ static int acpi_processor_get_performance_info(struct acpi_processor *pr)
         if (result)
                 goto update_bios;
 
-        return 0;
+        /* We need to call _PPC once when cpufreq starts */
+        if (ignore_ppc != 1)
+                result = acpi_processor_get_platform_limit(pr);
+
+        return result;
 
         /*
          * Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that