1 files changed, 417 insertions, 131 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 1b5853f384e2..14d0c89ada2a 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1,8 +1,8 @@
 /*
- *  ec.c - ACPI Embedded Controller Driver (v2.2)
+ *  ec.c - ACPI Embedded Controller Driver (v3)
  *
- *  Copyright (C) 2001-2014 Intel Corporation
- *    Author: 2014       Lv Zheng <lv.zheng@intel.com>
+ *  Copyright (C) 2001-2015 Intel Corporation
+ *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
  *            2004       Luming Yu <luming.yu@intel.com>
@@ -31,6 +31,7 @@
 
 /* Uncomment next line to get verbose printout */
 /* #define DEBUG */
+#define DEBUG_REF 0
 #define pr_fmt(fmt) "ACPI : EC: " fmt
 
 #include <linux/kernel.h>
@@ -71,20 +72,32 @@ 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_UDELAY_POLL     1000    /* Wait 1ms for EC transaction polling */
 #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 */
-        EC_FLAGS_GPE_STORM,             /* GPE storm detected */
+        EC_FLAGS_EVENT_ENABLED,         /* Event is enabled */
+        EC_FLAGS_EVENT_PENDING,         /* Event is pending */
+        EC_FLAGS_EVENT_DETECTED,        /* Event is detected */
         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
                                          * OpReg are installed */
-        EC_FLAGS_BLOCKED,               /* Transactions are blocked */
+        EC_FLAGS_STARTED,               /* Driver is started */
+        EC_FLAGS_STOPPED,               /* Driver is stopped */
+        EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
+                                         * current command processing */
 };
 
 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 
+#define ec_debug_ref(ec, fmt, ...)                                      \
+        do {                                                            \
+                if (DEBUG_REF)                                          \
+                        pr_debug("%lu: " fmt, ec->reference_count,      \
+                                 ## __VA_ARGS__);                       \
+        } while (0)
+
 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 module_param(ec_delay, uint, 0644);
@@ -105,6 +118,7 @@ struct acpi_ec_query_handler {
         acpi_handle handle;
         void *data;
         u8 query_bit;
+        struct kref kref;
 };
 
 struct transaction {
@@ -117,8 +131,12 @@ struct transaction {
         u8 wlen;
         u8 rlen;
         u8 flags;
+        unsigned long timestamp;
 };
 
+static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
+static void advance_transaction(struct acpi_ec *ec);
+
 struct acpi_ec *boot_ec, *first_ec;
 EXPORT_SYMBOL(first_ec);
 
@@ -129,7 +147,28 @@ static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 
 /* --------------------------------------------------------------------------
- *                           Transaction Management
+ *                           Device Flags
+ * -------------------------------------------------------------------------- */
+
+static bool acpi_ec_started(struct acpi_ec *ec)
+{
+        return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
+               !test_bit(EC_FLAGS_STOPPED, &ec->flags);
+}
+
+static bool acpi_ec_flushed(struct acpi_ec *ec)
+{
+        return ec->reference_count == 1;
+}
+
+static bool acpi_ec_has_pending_event(struct acpi_ec *ec)
+{
+        return test_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags) ||
+               test_bit(EC_FLAGS_EVENT_PENDING, &ec->flags);
+}
+
+/* --------------------------------------------------------------------------
+ *                           EC Registers
  * -------------------------------------------------------------------------- */
 
 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
@@ -151,6 +190,7 @@ static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 {
         u8 x = inb(ec->data_addr);
 
+        ec->curr->timestamp = jiffies;
         pr_debug("EC_DATA(R) = 0x%2.2x\n", x);
         return x;
 }
@@ -159,12 +199,14 @@ static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 {
         pr_debug("EC_SC(W) = 0x%2.2x\n", command);
         outb(command, ec->command_addr);
+        ec->curr->timestamp = jiffies;
 }
 
 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 {
         pr_debug("EC_DATA(W) = 0x%2.2x\n", data);
         outb(data, ec->data_addr);
+        ec->curr->timestamp = jiffies;
 }
 
 #ifdef DEBUG
@@ -188,6 +230,203 @@ static const char *acpi_ec_cmd_string(u8 cmd)
 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 #endif
 
+/* --------------------------------------------------------------------------
+ *                           GPE Registers
+ * -------------------------------------------------------------------------- */
+
+static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
+{
+        acpi_event_status gpe_status = 0;
+
+        (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
+        return (gpe_status & ACPI_EVENT_FLAG_SET) ? true : false;
+}
+
+static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
+{
+        if (open)
+                acpi_enable_gpe(NULL, ec->gpe);
+        else {
+                BUG_ON(ec->reference_count < 1);
+                acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
+        }
+        if (acpi_ec_is_gpe_raised(ec)) {
+                /*
+                 * On some platforms, EN=1 writes cannot trigger GPE. So
+                 * software need to manually trigger a pseudo GPE event on
+                 * EN=1 writes.
+                 */
+                pr_debug("***** Polling quirk *****\n");
+                advance_transaction(ec);
+        }
+}
+
+static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
+{
+        if (close)
+                acpi_disable_gpe(NULL, ec->gpe);
+        else {
+                BUG_ON(ec->reference_count < 1);
+                acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
+        }
+}
+
+static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
+{
+        /*
+         * GPE STS is a W1C register, which means:
+         * 1. Software can clear it without worrying about clearing other
+         *    GPEs' STS bits when the hardware sets them in parallel.
+         * 2. As long as software can ensure only clearing it when it is
+         *    set, hardware won't set it in parallel.
+         * So software can clear GPE in any contexts.
+         * Warning: do not move the check into advance_transaction() as the
+         * EC commands will be sent without GPE raised.
+         */
+        if (!acpi_ec_is_gpe_raised(ec))
+                return;
+        acpi_clear_gpe(NULL, ec->gpe);
+}
+
+/* --------------------------------------------------------------------------
+ *                           Transaction Management
+ * -------------------------------------------------------------------------- */
+
+static void acpi_ec_submit_request(struct acpi_ec *ec)
+{
+        ec->reference_count++;
+        if (ec->reference_count == 1)
+                acpi_ec_enable_gpe(ec, true);
+}
+
+static void acpi_ec_complete_request(struct acpi_ec *ec)
+{
+        bool flushed = false;
+
+        ec->reference_count--;
+        if (ec->reference_count == 0)
+                acpi_ec_disable_gpe(ec, true);
+        flushed = acpi_ec_flushed(ec);
+        if (flushed)
+                wake_up(&ec->wait);
+}
+
+static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
+{
+        if (!test_bit(flag, &ec->flags)) {
+                acpi_ec_disable_gpe(ec, false);
+                pr_debug("+++++ Polling enabled +++++\n");
+                set_bit(flag, &ec->flags);
+        }
+}
+
+static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
+{
+        if (test_bit(flag, &ec->flags)) {
+                clear_bit(flag, &ec->flags);
+                acpi_ec_enable_gpe(ec, false);
+                pr_debug("+++++ Polling disabled +++++\n");
+        }
+}
+
+/*
+ * acpi_ec_submit_flushable_request() - Increase the reference count unless
+ *                                      the flush operation is not in
+ *                                      progress
+ * @ec: the EC device
+ * @allow_event: whether event should be handled
+ *
+ * This function must be used before taking a new action that should hold
+ * the reference count.  If this function returns false, then the action
+ * must be discarded or it will prevent the flush operation from being
+ * completed.
+ *
+ * During flushing, QR_EC command need to pass this check when there is a
+ * pending event, so that the reference count held for the pending event
+ * can be decreased by the completion of the QR_EC command.
+ */
+static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec,
+                                             bool allow_event)
+{
+        if (!acpi_ec_started(ec)) {
+                if (!allow_event || !acpi_ec_has_pending_event(ec))
+                        return false;
+        }
+        acpi_ec_submit_request(ec);
+        return true;
+}
+
+static void acpi_ec_submit_event(struct acpi_ec *ec)
+{
+        if (!test_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags) ||
+            !test_bit(EC_FLAGS_EVENT_ENABLED, &ec->flags))
+                return;
+        /* Hold reference for pending event */
+        if (!acpi_ec_submit_flushable_request(ec, true))
+                return;
+        ec_debug_ref(ec, "Increase event\n");
+        if (!test_and_set_bit(EC_FLAGS_EVENT_PENDING, &ec->flags)) {
+                pr_debug("***** Event query started *****\n");
+                schedule_work(&ec->work);
+                return;
+        }
+        acpi_ec_complete_request(ec);
+        ec_debug_ref(ec, "Decrease event\n");
+}
+
+static void acpi_ec_complete_event(struct acpi_ec *ec)
+{
+        if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
+                clear_bit(EC_FLAGS_EVENT_PENDING, &ec->flags);
+                pr_debug("***** Event query stopped *****\n");
+                /* Unhold reference for pending event */
+                acpi_ec_complete_request(ec);
+                ec_debug_ref(ec, "Decrease event\n");
+                /* Check if there is another SCI_EVT detected */
+                acpi_ec_submit_event(ec);
+        }
+}
+
+static void acpi_ec_submit_detection(struct acpi_ec *ec)
+{
+        /* Hold reference for query submission */
+        if (!acpi_ec_submit_flushable_request(ec, false))
+                return;
+        ec_debug_ref(ec, "Increase query\n");
+        if (!test_and_set_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags)) {
+                pr_debug("***** Event detection blocked *****\n");
+                acpi_ec_submit_event(ec);
+                return;
+        }
+        acpi_ec_complete_request(ec);
+        ec_debug_ref(ec, "Decrease query\n");
+}
+
+static void acpi_ec_complete_detection(struct acpi_ec *ec)
+{
+        if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
+                clear_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags);
+                pr_debug("***** Event detetion unblocked *****\n");
+                /* Unhold reference for query submission */
+                acpi_ec_complete_request(ec);
+                ec_debug_ref(ec, "Decrease query\n");
+        }
+}
+
+static void acpi_ec_enable_event(struct acpi_ec *ec)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&ec->lock, flags);
+        set_bit(EC_FLAGS_EVENT_ENABLED, &ec->flags);
+        /*
+         * An event may be pending even with SCI_EVT=0, so QR_EC should
+         * always be issued right after started.
+         */
+        acpi_ec_submit_detection(ec);
+        spin_unlock_irqrestore(&ec->lock, flags);
+}
+
 static int ec_transaction_completed(struct acpi_ec *ec)
 {
         unsigned long flags;
@@ -200,7 +439,7 @@ static int ec_transaction_completed(struct acpi_ec *ec)
         return ret;
 }
 
-static bool advance_transaction(struct acpi_ec *ec)
+static void advance_transaction(struct acpi_ec *ec)
 {
         struct transaction *t;
         u8 status;
@@ -208,6 +447,12 @@ static bool advance_transaction(struct acpi_ec *ec)
 
         pr_debug("===== %s (%d) =====\n",
                  in_interrupt() ? "IRQ" : "TASK", smp_processor_id());
+        /*
+         * By always clearing STS before handling all indications, we can
+         * ensure a hardware STS 0->1 change after this clearing can always
+         * trigger a GPE interrupt.
+         */
+        acpi_ec_clear_gpe(ec);
         status = acpi_ec_read_status(ec);
         t = ec->curr;
         if (!t)
@@ -223,6 +468,7 @@ static bool advance_transaction(struct acpi_ec *ec)
                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
                                 if (t->rlen == t->ri) {
                                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
+                                        acpi_ec_complete_event(ec);
                                         if (t->command == ACPI_EC_COMMAND_QUERY)
                                                 pr_debug("***** Command(%s) hardware completion *****\n",
                                                          acpi_ec_cmd_string(t->command));
@@ -233,25 +479,29 @@ static bool advance_transaction(struct acpi_ec *ec)
                 } else if (t->wlen == t->wi &&
                            (status & ACPI_EC_FLAG_IBF) == 0) {
                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
+                        acpi_ec_complete_event(ec);
                         wakeup = true;
                 }
-                return wakeup;
+                goto out;
         } else {
                 if (EC_FLAGS_QUERY_HANDSHAKE &&
                     !(status & ACPI_EC_FLAG_SCI) &&
                     (t->command == ACPI_EC_COMMAND_QUERY)) {
                         t->flags |= ACPI_EC_COMMAND_POLL;
+                        acpi_ec_complete_detection(ec);
                         t->rdata[t->ri++] = 0x00;
                         t->flags |= ACPI_EC_COMMAND_COMPLETE;
+                        acpi_ec_complete_event(ec);
                         pr_debug("***** Command(%s) software completion *****\n",
                                  acpi_ec_cmd_string(t->command));
                         wakeup = true;
                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
                         acpi_ec_write_cmd(ec, t->command);
                         t->flags |= ACPI_EC_COMMAND_POLL;
+                        acpi_ec_complete_detection(ec);
                 } else
                         goto err;
-                return wakeup;
+                goto out;
         }
 err:
         /*
@@ -259,28 +509,27 @@ err:
          * otherwise will take a not handled IRQ as a false one.
          */
         if (!(status & ACPI_EC_FLAG_SCI)) {
-                if (in_interrupt() && t)
-                        ++t->irq_count;
+                if (in_interrupt() && t) {
+                        if (t->irq_count < ec_storm_threshold)
+                                ++t->irq_count;
+                        /* Allow triggering on 0 threshold */
+                        if (t->irq_count == ec_storm_threshold)
+                                acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
+                }
         }
-        return wakeup;
+out:
+        if (status & ACPI_EC_FLAG_SCI)
+                acpi_ec_submit_detection(ec);
+        if (wakeup && in_interrupt())
+                wake_up(&ec->wait);
 }
 
 static void start_transaction(struct acpi_ec *ec)
 {
         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
         ec->curr->flags = 0;
-        (void)advance_transaction(ec);
-}
-
-static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data);
-
-static int ec_check_sci_sync(struct acpi_ec *ec, u8 state)
-{
-        if (state & ACPI_EC_FLAG_SCI) {
-                if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
-                        return acpi_ec_sync_query(ec, NULL);
-        }
-        return 0;
+        ec->curr->timestamp = jiffies;
+        advance_transaction(ec);
 }
 
 static int ec_poll(struct acpi_ec *ec)
@@ -291,20 +540,25 @@ static int ec_poll(struct acpi_ec *ec)
         while (repeat--) {
                 unsigned long delay = jiffies +
                         msecs_to_jiffies(ec_delay);
+                unsigned long usecs = ACPI_EC_UDELAY_POLL;
                 do {
                         /* don't sleep with disabled interrupts */
                         if (EC_FLAGS_MSI || irqs_disabled()) {
-                                udelay(ACPI_EC_MSI_UDELAY);
+                                usecs = ACPI_EC_MSI_UDELAY;
+                                udelay(usecs);
                                 if (ec_transaction_completed(ec))
                                         return 0;
                         } else {
                                 if (wait_event_timeout(ec->wait,
                                                 ec_transaction_completed(ec),
-                                                msecs_to_jiffies(1)))
+                                                usecs_to_jiffies(usecs)))
                                         return 0;
                         }
                         spin_lock_irqsave(&ec->lock, flags);
-                        (void)advance_transaction(ec);
+                        if (time_after(jiffies,
+                                        ec->curr->timestamp +
+                                        usecs_to_jiffies(usecs)))
+                                advance_transaction(ec);
                         spin_unlock_irqrestore(&ec->lock, flags);
                 } while (time_before(jiffies, delay));
                 pr_debug("controller reset, restart transaction\n");
@@ -325,21 +579,29 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
                 udelay(ACPI_EC_MSI_UDELAY);
         /* start transaction */
         spin_lock_irqsave(&ec->lock, tmp);
+        /* Enable GPE for command processing (IBF=0/OBF=1) */
+        if (!acpi_ec_submit_flushable_request(ec, true)) {
+                ret = -EINVAL;
+                goto unlock;
+        }
+        ec_debug_ref(ec, "Increase command\n");
         /* following two actions should be kept atomic */
         ec->curr = t;
         pr_debug("***** Command(%s) started *****\n",
                  acpi_ec_cmd_string(t->command));
         start_transaction(ec);
-        if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
-                clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
-                pr_debug("***** Event stopped *****\n");
-        }
         spin_unlock_irqrestore(&ec->lock, tmp);
         ret = ec_poll(ec);
         spin_lock_irqsave(&ec->lock, tmp);
+        if (t->irq_count == ec_storm_threshold)
+                acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
         pr_debug("***** Command(%s) stopped *****\n",
                  acpi_ec_cmd_string(t->command));
         ec->curr = NULL;
+        /* Disable GPE for command processing (IBF=0/OBF=1) */
+        acpi_ec_complete_request(ec);
+        ec_debug_ref(ec, "Decrease command\n");
+unlock:
         spin_unlock_irqrestore(&ec->lock, tmp);
         return ret;
 }
@@ -354,10 +616,6 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
         if (t->rdata)
                 memset(t->rdata, 0, t->rlen);
         mutex_lock(&ec->mutex);
-        if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
-                status = -EINVAL;
-                goto unlock;
-        }
         if (ec->global_lock) {
                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
                 if (ACPI_FAILURE(status)) {
@@ -365,26 +623,11 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
                         goto unlock;
                 }
         }
-        /* disable GPE during transaction if storm is detected */
-        if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
-                /* It has to be disabled, so that it doesn't trigger. */
-                acpi_disable_gpe(NULL, ec->gpe);
-        }
 
         status = acpi_ec_transaction_unlocked(ec, t);
 
-        /* check if we received SCI during transaction */
-        ec_check_sci_sync(ec, acpi_ec_read_status(ec));
-        if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
+        if (test_bit(EC_FLAGS_COMMAND_STORM, &ec->flags))
                 msleep(1);
-                /* It is safe to enable the GPE outside of the transaction. */
-                acpi_enable_gpe(NULL, ec->gpe);
-        } else if (t->irq_count > ec_storm_threshold) {
-                pr_info("GPE storm detected(%d GPEs), "
-                        "transactions will use polling mode\n",
-                        t->irq_count);
-                set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
-        }
         if (ec->global_lock)
                 acpi_release_global_lock(glk);
 unlock:
@@ -500,7 +743,7 @@ static void acpi_ec_clear(struct acpi_ec *ec)
         u8 value = 0;
 
         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
-                status = acpi_ec_sync_query(ec, &value);
+                status = acpi_ec_query(ec, &value);
                 if (status || !value)
                         break;
         }
@@ -511,6 +754,57 @@ static void acpi_ec_clear(struct acpi_ec *ec)
                 pr_info("%d stale EC events cleared\n", i);
 }
 
+static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&ec->lock, flags);
+        if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
+                pr_debug("+++++ Starting EC +++++\n");
+                /* Enable GPE for event processing (SCI_EVT=1) */
+                if (!resuming) {
+                        acpi_ec_submit_request(ec);
+                        ec_debug_ref(ec, "Increase driver\n");
+                }
+                pr_info("+++++ EC started +++++\n");
+        }
+        spin_unlock_irqrestore(&ec->lock, flags);
+}
+
+static bool acpi_ec_stopped(struct acpi_ec *ec)
+{
+        unsigned long flags;
+        bool flushed;
+
+        spin_lock_irqsave(&ec->lock, flags);
+        flushed = acpi_ec_flushed(ec);
+        spin_unlock_irqrestore(&ec->lock, flags);
+        return flushed;
+}
+
+static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&ec->lock, flags);
+        if (acpi_ec_started(ec)) {
+                pr_debug("+++++ Stopping EC +++++\n");
+                set_bit(EC_FLAGS_STOPPED, &ec->flags);
+                spin_unlock_irqrestore(&ec->lock, flags);
+                wait_event(ec->wait, acpi_ec_stopped(ec));
+                spin_lock_irqsave(&ec->lock, flags);
+                /* Disable GPE for event processing (SCI_EVT=1) */
+                if (!suspending) {
+                        acpi_ec_complete_request(ec);
+                        ec_debug_ref(ec, "Decrease driver\n");
+                }
+                clear_bit(EC_FLAGS_STARTED, &ec->flags);
+                clear_bit(EC_FLAGS_STOPPED, &ec->flags);
+                pr_info("+++++ EC stopped +++++\n");
+        }
+        spin_unlock_irqrestore(&ec->lock, flags);
+}
+
 void acpi_ec_block_transactions(void)
 {
         struct acpi_ec *ec = first_ec;
@@ -520,7 +814,7 @@ void acpi_ec_block_transactions(void)
 
         mutex_lock(&ec->mutex);
         /* Prevent transactions from being carried out */
-        set_bit(EC_FLAGS_BLOCKED, &ec->flags);
+        acpi_ec_stop(ec, true);
         mutex_unlock(&ec->mutex);
 }
 
@@ -531,14 +825,11 @@ void acpi_ec_unblock_transactions(void)
         if (!ec)
                 return;
 
-        mutex_lock(&ec->mutex);
         /* Allow transactions to be carried out again */
-        clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
+        acpi_ec_start(ec, true);
 
         if (EC_FLAGS_CLEAR_ON_RESUME)
                 acpi_ec_clear(ec);
-
-        mutex_unlock(&ec->mutex);
 }
 
 void acpi_ec_unblock_transactions_early(void)
@@ -548,36 +839,33 @@ void acpi_ec_unblock_transactions_early(void)
          * atomic context during wakeup, so we don't need to acquire the mutex).
          */
         if (first_ec)
-                clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
+                acpi_ec_start(first_ec, true);
 }
 
-static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 *data)
+/* --------------------------------------------------------------------------
+                                Event Management
+   -------------------------------------------------------------------------- */
+static struct acpi_ec_query_handler *
+acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
 {
-        int result;
-        u8 d;
-        struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
-                                .wdata = NULL, .rdata = &d,
-                                .wlen = 0, .rlen = 1};
+        if (handler)
+                kref_get(&handler->kref);
+        return handler;
+}
 
-        if (!ec || !data)
-                return -EINVAL;
-        /*
-         * Query the EC to find out which _Qxx method we need to evaluate.
-         * Note that successful completion of the query causes the ACPI_EC_SCI
-         * bit to be cleared (and thus clearing the interrupt source).
-         */
-        result = acpi_ec_transaction_unlocked(ec, &t);
-        if (result)
-                return result;
-        if (!d)
-                return -ENODATA;
-        *data = d;
-        return 0;
+static void acpi_ec_query_handler_release(struct kref *kref)
+{
+        struct acpi_ec_query_handler *handler =
+                container_of(kref, struct acpi_ec_query_handler, kref);
+
+        kfree(handler);
+}
+
+static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
+{
+        kref_put(&handler->kref, acpi_ec_query_handler_release);
 }
 
-/* --------------------------------------------------------------------------
-                                Event Management
-   -------------------------------------------------------------------------- */
 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
                               acpi_handle handle, acpi_ec_query_func func,
                               void *data)
@@ -593,6 +881,7 @@ int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
         handler->func = func;
         handler->data = data;
         mutex_lock(&ec->mutex);
+        kref_init(&handler->kref);
         list_add(&handler->node, &ec->list);
         mutex_unlock(&ec->mutex);
         return 0;
@@ -602,15 +891,18 @@ EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
 {
         struct acpi_ec_query_handler *handler, *tmp;
+        LIST_HEAD(free_list);
 
         mutex_lock(&ec->mutex);
         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
                 if (query_bit == handler->query_bit) {
-                        list_del(&handler->node);
-                        kfree(handler);
+                        list_del_init(&handler->node);
+                        list_add(&handler->node, &free_list);
                 }
         }
         mutex_unlock(&ec->mutex);
+        list_for_each_entry(handler, &free_list, node)
+                acpi_ec_put_query_handler(handler);
 }
 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
 
@@ -626,59 +918,58 @@ static void acpi_ec_run(void *cxt)
         else if (handler->handle)
                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
         pr_debug("##### Query(0x%02x) stopped #####\n", handler->query_bit);
-        kfree(handler);
+        acpi_ec_put_query_handler(handler);
 }
 
-static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data)
+static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
 {
         u8 value = 0;
-        int status;
-        struct acpi_ec_query_handler *handler, *copy;
+        int result;
+        acpi_status status;
+        struct acpi_ec_query_handler *handler;
+        struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
+                                .wdata = NULL, .rdata = &value,
+                                .wlen = 0, .rlen = 1};
 
-        status = acpi_ec_query_unlocked(ec, &value);
+        /*
+         * Query the EC to find out which _Qxx method we need to evaluate.
+         * Note that successful completion of the query causes the ACPI_EC_SCI
+         * bit to be cleared (and thus clearing the interrupt source).
+         */
+        result = acpi_ec_transaction(ec, &t);
+        if (result)
+                return result;
         if (data)
                 *data = value;
-        if (status)
-                return status;
+        if (!value)
+                return -ENODATA;
 
+        mutex_lock(&ec->mutex);
         list_for_each_entry(handler, &ec->list, node) {
                 if (value == handler->query_bit) {
                         /* have custom handler for this bit */
-                        copy = kmalloc(sizeof(*handler), GFP_KERNEL);
-                        if (!copy)
-                                return -ENOMEM;
-                        memcpy(copy, handler, sizeof(*copy));
+                        handler = acpi_ec_get_query_handler(handler);
                         pr_debug("##### Query(0x%02x) scheduled #####\n",
                                  handler->query_bit);
-                        return acpi_os_execute((copy->func) ?
+                        status = acpi_os_execute((handler->func) ?
                                 OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
-                                acpi_ec_run, copy);
+                                acpi_ec_run, handler);
+                        if (ACPI_FAILURE(status))
+                                result = -EBUSY;
+                        break;
                 }
         }
-        return 0;
-}
-
-static void acpi_ec_gpe_query(void *ec_cxt)
-{
-        struct acpi_ec *ec = ec_cxt;
-
-        if (!ec)
-                return;
-        mutex_lock(&ec->mutex);
-        acpi_ec_sync_query(ec, NULL);
         mutex_unlock(&ec->mutex);
+        return result;
 }
 
-static int ec_check_sci(struct acpi_ec *ec, u8 state)
+static void acpi_ec_gpe_poller(struct work_struct *work)
 {
-        if (state & ACPI_EC_FLAG_SCI) {
-                if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
-                        pr_debug("***** Event started *****\n");
-                        return acpi_os_execute(OSL_NOTIFY_HANDLER,
-                                acpi_ec_gpe_query, ec);
-                }
-        }
-        return 0;
+        struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
+
+        pr_debug("***** Event poller started *****\n");
+        acpi_ec_query(ec, NULL);
+        pr_debug("***** Event poller stopped *****\n");
 }
 
 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
@@ -688,11 +979,9 @@ static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
         struct acpi_ec *ec = data;
 
         spin_lock_irqsave(&ec->lock, flags);
-        if (advance_transaction(ec))
-                wake_up(&ec->wait);
+        advance_transaction(ec);
         spin_unlock_irqrestore(&ec->lock, flags);
-        ec_check_sci(ec, acpi_ec_read_status(ec));
-        return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
+        return ACPI_INTERRUPT_HANDLED;
 }
 
 /* --------------------------------------------------------------------------
@@ -750,11 +1039,11 @@ static struct acpi_ec *make_acpi_ec(void)
 
         if (!ec)
                 return NULL;
-        ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
         mutex_init(&ec->mutex);
         init_waitqueue_head(&ec->wait);
         INIT_LIST_HEAD(&ec->list);
         spin_lock_init(&ec->lock);
+        INIT_WORK(&ec->work, acpi_ec_gpe_poller);
         return ec;
 }
 
@@ -810,13 +1099,13 @@ static int ec_install_handlers(struct acpi_ec *ec)
 
         if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
                 return 0;
-        status = acpi_install_gpe_handler(NULL, ec->gpe,
+        status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
                                   ACPI_GPE_EDGE_TRIGGERED,
                                   &acpi_ec_gpe_handler, ec);
         if (ACPI_FAILURE(status))
                 return -ENODEV;
 
-        acpi_enable_gpe(NULL, ec->gpe);
+        acpi_ec_start(ec, false);
         status = acpi_install_address_space_handler(ec->handle,
                                                     ACPI_ADR_SPACE_EC,
                                                     &acpi_ec_space_handler,
@@ -831,7 +1120,7 @@ static int ec_install_handlers(struct acpi_ec *ec)
                         pr_err("Fail in evaluating the _REG object"
                                 " of EC device. Broken bios is suspected.\n");
                 } else {
-                        acpi_disable_gpe(NULL, ec->gpe);
+                        acpi_ec_stop(ec, false);
                         acpi_remove_gpe_handler(NULL, ec->gpe,
                                 &acpi_ec_gpe_handler);
                         return -ENODEV;
@@ -846,7 +1135,7 @@ static void ec_remove_handlers(struct acpi_ec *ec)
 {
         if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
                 return;
-        acpi_disable_gpe(NULL, ec->gpe);
+        acpi_ec_stop(ec, false);
         if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
                                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
                 pr_err("failed to remove space handler\n");
@@ -900,14 +1189,11 @@ static int acpi_ec_add(struct acpi_device *device)
         ret = ec_install_handlers(ec);
 
         /* EC is fully operational, allow queries */
-        clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
+        acpi_ec_enable_event(ec);
 
         /* Clear stale _Q events if hardware might require that */
-        if (EC_FLAGS_CLEAR_ON_RESUME) {
-                mutex_lock(&ec->mutex);
+        if (EC_FLAGS_CLEAR_ON_RESUME)
                 acpi_ec_clear(ec);
-                mutex_unlock(&ec->mutex);
-        }
         return ret;
 }