ACPI / ACPICA: Fix low-level GPE manipulation code

ACPICA uses acpi_ev_enable_gpe() for enabling GPEs at the low level,
which is incorrect, because this function only enables the GPE if the
corresponding bit in its enable register's enable_for_run mask is set.
This causes acpi_set_gpe() to work incorrectly if used for enabling
GPEs that were not previously enabled with acpi_enable_gpe().  As a
result, among other things, wakeup-only GPEs are never enabled by
acpi_enable_wakeup_device(), so the devices that use them are unable
to wake up the system.

To fix this issue remove acpi_ev_enable_gpe() and its counterpart
acpi_ev_disable_gpe() and replace acpi_hw_low_disable_gpe() with
acpi_hw_low_set_gpe() that will be used instead to manipulate GPE
enable bits at the low level.  Make the users of acpi_ev_enable_gpe()
and acpi_ev_disable_gpe() call acpi_hw_low_set_gpe() instead and
make sure that GPE enable masks are only updated by acpi_enable_gpe()
and acpi_disable_gpe() when GPE reference counters change from 0
to 1 and from 1 to 0, respectively.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 53 insertions, 6 deletions

diff --git a/drivers/acpi/acpica/evxfevnt.c b/drivers/acpi/acpica/evxfevnt.c
index 7c7bbb4d402c..e3d9f5c8e53d 100644
--- a/drivers/acpi/acpica/evxfevnt.c
+++ b/drivers/acpi/acpica/evxfevnt.c
@@ -201,6 +201,44 @@ ACPI_EXPORT_SYMBOL(acpi_enable_event)
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_clear_and_enable_gpe
+ *
+ * PARAMETERS:  gpe_event_info  - GPE to enable
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Clear the given GPE from stale events and enable it.
+ *
+ ******************************************************************************/
+static acpi_status
+acpi_clear_and_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
+{
+        acpi_status status;
+
+        /*
+         * We will only allow a GPE to be enabled if it has either an
+         * associated method (_Lxx/_Exx) or a handler. Otherwise, the
+         * GPE will be immediately disabled by acpi_ev_gpe_dispatch the
+         * first time it fires.
+         */
+        if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)) {
+                return_ACPI_STATUS(AE_NO_HANDLER);
+        }
+
+        /* Clear the GPE (of stale events) */
+        status = acpi_hw_clear_gpe(gpe_event_info);
+        if (ACPI_FAILURE(status)) {
+                return_ACPI_STATUS(status);
+        }
+
+        /* Enable the requested GPE */
+        status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE);
+
+        return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_set_gpe
  *
  * PARAMETERS:  gpe_device      - Parent GPE Device. NULL for GPE0/GPE1
@@ -240,11 +278,11 @@ acpi_status acpi_set_gpe(acpi_handle gpe_device, u32 gpe_number, u8 action)
 
         switch (action) {
         case ACPI_GPE_ENABLE:
-                status = acpi_ev_enable_gpe(gpe_event_info);
+                status = acpi_clear_and_enable_gpe(gpe_event_info);
                 break;
 
         case ACPI_GPE_DISABLE:
-                status = acpi_ev_disable_gpe(gpe_event_info);
+                status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
                 break;
 
         default:
@@ -307,7 +345,11 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type)
 
                 gpe_event_info->runtime_count++;
                 if (gpe_event_info->runtime_count == 1) {
-                        status = acpi_ev_enable_gpe(gpe_event_info);
+                        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
+                        if (ACPI_SUCCESS(status)) {
+                                status = acpi_clear_and_enable_gpe(gpe_event_info);
+                        }
+
                         if (ACPI_FAILURE(status)) {
                                 gpe_event_info->runtime_count--;
                                 goto unlock_and_exit;
@@ -334,7 +376,7 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type)
                  */
                 gpe_event_info->wakeup_count++;
                 if (gpe_event_info->wakeup_count == 1) {
-                        (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
+                        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
                 }
         }
 
@@ -394,7 +436,12 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type
 
                 gpe_event_info->runtime_count--;
                 if (!gpe_event_info->runtime_count) {
-                        status = acpi_ev_disable_gpe(gpe_event_info);
+                        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
+                        if (ACPI_SUCCESS(status)) {
+                                status = acpi_hw_low_set_gpe(gpe_event_info,
+                                                             ACPI_GPE_DISABLE);
+                        }
+
                         if (ACPI_FAILURE(status)) {
                                 gpe_event_info->runtime_count++;
                                 goto unlock_and_exit;
@@ -415,7 +462,7 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type
 
                 gpe_event_info->wakeup_count--;
                 if (!gpe_event_info->wakeup_count) {
-                        (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
+                        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
                 }
         }