2 files changed, 44 insertions, 2 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 85cbfdccc97c..c8a1f3b68110 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1567,6 +1567,7 @@ static int acpi_bus_scan_fixed(void)
                                                 ACPI_BUS_TYPE_POWER_BUTTON,
                                                 ACPI_STA_DEFAULT,
                                                 &ops);
+                device_init_wakeup(&device->dev, true);
         }
 
         if ((acpi_gbl_FADT.flags & ACPI_FADT_SLEEP_BUTTON) == 0) {
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index eb6fd233764b..a564fc3ffa1c 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -57,6 +57,7 @@ MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
 MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
 
 static u8 sleep_states[ACPI_S_STATE_COUNT];
+static bool pwr_btn_event_pending;
 
 static void acpi_sleep_tts_switch(u32 acpi_state)
 {
@@ -186,6 +187,14 @@ static int acpi_pm_prepare(void)
         return error;
 }
 
+static int find_powerf_dev(struct device *dev, void *data)
+{
+        struct acpi_device *device = to_acpi_device(dev);
+        const char *hid = acpi_device_hid(device);
+
+        return !strcmp(hid, ACPI_BUTTON_HID_POWERF);
+}
+
 /**
  *      acpi_pm_finish - Instruct the platform to leave a sleep state.
  *
@@ -194,6 +203,7 @@ static int acpi_pm_prepare(void)
  */
 static void acpi_pm_finish(void)
 {
+        struct device *pwr_btn_dev;
         u32 acpi_state = acpi_target_sleep_state;
 
         acpi_ec_unblock_transactions();
@@ -211,6 +221,23 @@ static void acpi_pm_finish(void)
         acpi_set_firmware_waking_vector((acpi_physical_address) 0);
 
         acpi_target_sleep_state = ACPI_STATE_S0;
+
+        /* If we were woken with the fixed power button, provide a small
+         * hint to userspace in the form of a wakeup event on the fixed power
+         * button device (if it can be found).
+         *
+         * We delay the event generation til now, as the PM layer requires
+         * timekeeping to be running before we generate events. */
+        if (!pwr_btn_event_pending)
+                return;
+
+        pwr_btn_event_pending = false;
+        pwr_btn_dev = bus_find_device(&acpi_bus_type, NULL, NULL,
+                                      find_powerf_dev);
+        if (pwr_btn_dev) {
+                pm_wakeup_event(pwr_btn_dev, 0);
+                put_device(pwr_btn_dev);
+        }
 }
 
 /**
@@ -300,9 +327,23 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
         /* ACPI 3.0 specs (P62) says that it's the responsibility
          * of the OSPM to clear the status bit [ implying that the
          * POWER_BUTTON event should not reach userspace ]
+         *
+         * However, we do generate a small hint for userspace in the form of
+         * a wakeup event. We flag this condition for now and generate the
+         * event later, as we're currently too early in resume to be able to
+         * generate wakeup events.
          */
-        if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3))
-                acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
+        if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3)) {
+                acpi_event_status pwr_btn_status;
+
+                acpi_get_event_status(ACPI_EVENT_POWER_BUTTON, &pwr_btn_status);
+
+                if (pwr_btn_status & ACPI_EVENT_FLAG_SET) {
+                        acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
+                        /* Flag for later */
+                        pwr_btn_event_pending = true;
+                }
+        }
 
         /*
          * Disable and clear GPE status before interrupt is enabled. Some GPEs