Make GPE disable more robust

Implemented another change for the GPE disable. We now perform a
read-change-write of the enable register instead of simply writing out the
cached enable mask. This will prevent inadvertent enabling of GPEs if a rogue
GPE is received during initialization (before GPE handlers are installed.)

http://bugzilla.kernel.org/show_bug.cgi?id=6217

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 14 insertions, 4 deletions

diff --git a/drivers/acpi/events/evgpe.c b/drivers/acpi/events/evgpe.c
index 5354be4..e0339d4 100644
--- a/drivers/acpi/events/evgpe.c
+++ b/drivers/acpi/events/evgpe.c
@@ -256,7 +256,7 @@ acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 		return_ACPI_STATUS(status);
 	}
 
-	/* Mark wake-disabled or HW disable, or both */
+	/* Clear the appropriate enabled flags for this GPE */
 
 	switch (gpe_event_info->flags & ACPI_GPE_TYPE_MASK) {
 	case ACPI_GPE_TYPE_WAKE:
@@ -273,13 +273,23 @@ acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 		/* Disable the requested runtime GPE */
 
 		ACPI_CLEAR_BIT(gpe_event_info->flags, ACPI_GPE_RUN_ENABLED);
-
-		/* fallthrough */
+		break;
 
 	default:
-		acpi_hw_write_gpe_enable_reg(gpe_event_info);
+		break;
 	}
 
+	/*
+	 * Even if we don't know the GPE type, make sure that we always
+	 * disable it. low_disable_gpe will just clear the enable bit for this
+	 * GPE and write it. It will not write out the current GPE enable mask,
+	 * since this may inadvertently enable GPEs too early, if a rogue GPE has
+	 * come in during ACPICA initialization - possibly as a result of AML or
+	 * other code that has enabled the GPE.
+	 */
+	status = acpi_hw_low_disable_gpe(gpe_event_info);
+	return_ACPI_STATUS(status);
+
 	return_ACPI_STATUS(AE_OK);
 }