Merge tag 'pm+acpi-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management updates from Rafael Wysocki:
 "We have a few new features this time, including a new SFI-based
  cpufreq driver, a new devfreq driver for Tegra Activity Monitor, a new
  devfreq class for providing its governors with raw utilization data
  and a new ACPI driver for AMD SoCs.

  Still, the majority of changes here are reworks of existing code to
  make it more straightforward or to prepare it for implementing new
  features on top of it.  The primary example is the rework of ACPI
  resources handling from Jiang Liu, Thomas Gleixner and Lv Zheng with
  support for IOAPIC hotplug implemented on top of it, but there is
  quite a number of changes of this kind in the cpufreq core, ACPICA,
  ACPI EC driver, ACPI processor driver and the generic power domains
  core code too.

  The most active developer is Viresh Kumar with his cpufreq changes.

  Specifics:

   - Rework of the core ACPI resources parsing code to fix issues in it
     and make using resource offsets more convenient and consolidation
     of some resource-handing code in a couple of places that have grown
     analagous data structures and code to cover the the same gap in the
     core (Jiang Liu, Thomas Gleixner, Lv Zheng).

   - ACPI-based IOAPIC hotplug support on top of the resources handling
     rework (Jiang Liu, Yinghai Lu).

   - ACPICA update to upstream release 20150204 including an interrupt
     handling rework that allows drivers to install raw handlers for
     ACPI GPEs which then become entirely responsible for the given GPE
     and the ACPICA core code won't touch it (Lv Zheng, David E Box,
     Octavian Purdila).

   - ACPI EC driver rework to fix several concurrency issues and other
     problems related to events handling on top of the ACPICA's new
     support for raw GPE handlers (Lv Zheng).

   - New ACPI driver for AMD SoCs analogous to the LPSS (Low-Power
     Subsystem) driver for Intel chips (Ken Xue).

   - Two minor fixes of the ACPI LPSS driver (Heikki Krogerus, Jarkko
     Nikula).

   - Two new blacklist entries for machines (Samsung 730U3E/740U3E and
     510R) where the native backlight interface doesn't work correctly
     while the ACPI one does (Hans de Goede).

   - Rework of the ACPI processor driver's handling of idle states to
     make the code more straightforward and less bloated overall (Rafael
     J Wysocki).

   - Assorted minor fixes related to ACPI and SFI (Andreas Ruprecht,
     Andy Shevchenko, Hanjun Guo, Jan Beulich, Rafael J Wysocki, Yaowei
     Bai).

   - PCI core power management modification to avoid resuming (some)
     runtime-suspended devices during system suspend if they are in the
     right states already (Rafael J Wysocki).

   - New SFI-based cpufreq driver for Intel platforms using SFI
     (Srinidhi Kasagar).

   - cpufreq core fixes, cleanups and simplifications (Viresh Kumar,
     Doug Anderson, Wolfram Sang).

   - SkyLake CPU support and other updates for the intel_pstate driver
     (Kristen Carlson Accardi, Srinivas Pandruvada).

   - cpufreq-dt driver cleanup (Markus Elfring).

   - Init fix for the ARM big.LITTLE cpuidle driver (Sudeep Holla).

   - Generic power domains core code fixes and cleanups (Ulf Hansson).

   - Operating Performance Points (OPP) core code cleanups and kernel
     documentation update (Nishanth Menon).

   - New dabugfs interface to make the list of PM QoS constraints
     available to user space (Nishanth Menon).

   - New devfreq driver for Tegra Activity Monitor (Tomeu Vizoso).

   - New devfreq class (devfreq_event) to provide raw utilization data
     to devfreq governors (Chanwoo Choi).

   - Assorted minor fixes and cleanups related to power management
     (Andreas Ruprecht, Krzysztof Kozlowski, Rickard Strandqvist, Pavel
     Machek, Todd E Brandt, Wonhong Kwon).

   - turbostat updates (Len Brown) and cpupower Makefile improvement
     (Sriram Raghunathan)"

* tag 'pm+acpi-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (151 commits)
  tools/power turbostat: relax dependency on APERF_MSR
  tools/power turbostat: relax dependency on invariant TSC
  Merge branch 'pci/host-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci into acpi-resources
  tools/power turbostat: decode MSR_*_PERF_LIMIT_REASONS
  tools/power turbostat: relax dependency on root permission
  ACPI / video: Add disable_native_backlight quirk for Samsung 510R
  ACPI / PM: Remove unneeded nested #ifdef
  USB / PM: Remove unneeded #ifdef and associated dead code
  intel_pstate: provide option to only use intel_pstate with HWP
  ACPI / EC: Add GPE reference counting debugging messages
  ACPI / EC: Add query flushing support
  ACPI / EC: Refine command storm prevention support
  ACPI / EC: Add command flushing support.
  ACPI / EC: Introduce STARTED/STOPPED flags to replace BLOCKED flag
  ACPI: add AMD ACPI2Platform device support for x86 system
  ACPI / table: remove duplicate NULL check for the handler of acpi_table_parse()
  ACPI / EC: Update revision due to raw handler mode.
  ACPI / EC: Reduce ec_poll() by referencing the last register access timestamp.
  ACPI / EC: Fix several GPE handling issues by deploying ACPI_GPE_DISPATCH_RAW_HANDLER mode.
  ACPICA: Events: Enable APIs to allow interrupt/polling adaptive request based GPE handling model
  ...

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;
 }