3 files changed, 80 insertions, 1 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 959d41acc108..d7d32c28829b 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -67,6 +67,8 @@ enum ec_command {
 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
 #define ACPI_EC_MSI_UDELAY      550     /* Wait 550us for MSI EC */
+#define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
+                                         * when trying to clear the EC */
 
 enum {
         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
@@ -116,6 +118,7 @@ EXPORT_SYMBOL(first_ec);
 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
+static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 
 /* --------------------------------------------------------------------------
                              Transaction Management
@@ -440,6 +443,29 @@ acpi_handle ec_get_handle(void)
 
 EXPORT_SYMBOL(ec_get_handle);
 
+static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 *data);
+
+/*
+ * Clears stale _Q events that might have accumulated in the EC.
+ * Run with locked ec mutex.
+ */
+static void acpi_ec_clear(struct acpi_ec *ec)
+{
+        int i, status;
+        u8 value = 0;
+
+        for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
+                status = acpi_ec_query_unlocked(ec, &value);
+                if (status || !value)
+                        break;
+        }
+
+        if (unlikely(i == ACPI_EC_CLEAR_MAX))
+                pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
+        else
+                pr_info("%d stale EC events cleared\n", i);
+}
+
 void acpi_ec_block_transactions(void)
 {
         struct acpi_ec *ec = first_ec;
@@ -463,6 +489,10 @@ void acpi_ec_unblock_transactions(void)
         mutex_lock(&ec->mutex);
         /* Allow transactions to be carried out again */
         clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
+
+        if (EC_FLAGS_CLEAR_ON_RESUME)
+                acpi_ec_clear(ec);
+
         mutex_unlock(&ec->mutex);
 }
 
@@ -821,6 +851,13 @@ static int acpi_ec_add(struct acpi_device *device)
 
         /* EC is fully operational, allow queries */
         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
+
+        /* Clear stale _Q events if hardware might require that */
+        if (EC_FLAGS_CLEAR_ON_RESUME) {
+                mutex_lock(&ec->mutex);
+                acpi_ec_clear(ec);
+                mutex_unlock(&ec->mutex);
+        }
         return ret;
 }
 
@@ -922,6 +959,30 @@ static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
         return 0;
 }
 
+/*
+ * On some hardware it is necessary to clear events accumulated by the EC during
+ * sleep. These ECs stop reporting GPEs until they are manually polled, if too
+ * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
+ *
+ * https://bugzilla.kernel.org/show_bug.cgi?id=44161
+ *
+ * Ideally, the EC should also be instructed NOT to accumulate events during
+ * sleep (which Windows seems to do somehow), but the interface to control this
+ * behaviour is not known at this time.
+ *
+ * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
+ * however it is very likely that other Samsung models are affected.
+ *
+ * On systems which don't accumulate _Q events during sleep, this extra check
+ * should be harmless.
+ */
+static int ec_clear_on_resume(const struct dmi_system_id *id)
+{
+        pr_debug("Detected system needing EC poll on resume.\n");
+        EC_FLAGS_CLEAR_ON_RESUME = 1;
+        return 0;
+}
+
 static struct dmi_system_id ec_dmi_table[] __initdata = {
         {
         ec_skip_dsdt_scan, "Compal JFL92", {
@@ -965,6 +1026,9 @@ static struct dmi_system_id ec_dmi_table[] __initdata = {
         ec_validate_ecdt, "ASUS hardware", {
         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
+        {
+        ec_clear_on_resume, "Samsung hardware", {
+        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
         {},
 };
 
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index b7201fc6f1e1..0bdacc5e26a3 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -77,18 +77,24 @@ bool acpi_dev_resource_memory(struct acpi_resource *ares, struct resource *res)
         switch (ares->type) {
         case ACPI_RESOURCE_TYPE_MEMORY24:
                 memory24 = &ares->data.memory24;
+                if (!memory24->address_length)
+                        return false;
                 acpi_dev_get_memresource(res, memory24->minimum,
                                          memory24->address_length,
                                          memory24->write_protect);
                 break;
         case ACPI_RESOURCE_TYPE_MEMORY32:
                 memory32 = &ares->data.memory32;
+                if (!memory32->address_length)
+                        return false;
                 acpi_dev_get_memresource(res, memory32->minimum,
                                          memory32->address_length,
                                          memory32->write_protect);
                 break;
         case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
                 fixed_memory32 = &ares->data.fixed_memory32;
+                if (!fixed_memory32->address_length)
+                        return false;
                 acpi_dev_get_memresource(res, fixed_memory32->address,
                                          fixed_memory32->address_length,
                                          fixed_memory32->write_protect);
@@ -144,12 +150,16 @@ bool acpi_dev_resource_io(struct acpi_resource *ares, struct resource *res)
         switch (ares->type) {
         case ACPI_RESOURCE_TYPE_IO:
                 io = &ares->data.io;
+                if (!io->address_length)
+                        return false;
                 acpi_dev_get_ioresource(res, io->minimum,
                                         io->address_length,
                                         io->io_decode);
                 break;
         case ACPI_RESOURCE_TYPE_FIXED_IO:
                 fixed_io = &ares->data.fixed_io;
+                if (!fixed_io->address_length)
+                        return false;
                 acpi_dev_get_ioresource(res, fixed_io->address,
                                         fixed_io->address_length,
                                         ACPI_DECODE_10);
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index b718806657cd..b0f6c4a2a119 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -807,7 +807,12 @@ int __init acpi_sleep_init(void)
         acpi_sleep_hibernate_setup();
 
         status = acpi_get_sleep_type_data(ACPI_STATE_S5, &type_a, &type_b);
-        if (ACPI_SUCCESS(status)) {
+        /*
+         * Check both ACPI S5 object and ACPI sleep registers to
+         * install pm_power_off_prepare/pm_power_off hook
+         */
+        if (ACPI_SUCCESS(status) && acpi_gbl_FADT.sleep_control.address
+            && acpi_gbl_FADT.sleep_status.address) {
                 sleep_states[ACPI_STATE_S5] = 1;
                 pm_power_off_prepare = acpi_power_off_prepare;
                 pm_power_off = acpi_power_off;