Revert "ACPI / EC: Add query flushing support"

Revert commit f252cb09e1cb (ACPI / EC: Add query flushing support),
because it breaks system suspend on Acer Aspire S5.  The machine
just hangs solid at the last stage of suspend (after taking non-boot
CPUs offline).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 16 insertions, 85 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 40002ae7db2b..982b67faaaf3 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -76,9 +76,7 @@ enum ec_command {
                                          * when trying to clear the EC */
 
 enum {
-        EC_FLAGS_EVENT_ENABLED,         /* Event is enabled */
-        EC_FLAGS_EVENT_PENDING,         /* Event is pending */
-        EC_FLAGS_EVENT_DETECTED,        /* Event is detected */
+        EC_FLAGS_QUERY_PENDING,         /* Query is pending */
         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
                                          * OpReg are installed */
         EC_FLAGS_STARTED,               /* Driver is started */
@@ -153,12 +151,6 @@ 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
  * -------------------------------------------------------------------------- */
@@ -326,93 +318,36 @@ static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
  *                                      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)
+static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 {
-        if (!acpi_ec_started(ec)) {
-                if (!allow_event || !acpi_ec_has_pending_event(ec))
-                        return false;
-        }
+        if (!acpi_ec_started(ec))
+                return false;
         acpi_ec_submit_request(ec);
         return true;
 }
 
-static void acpi_ec_submit_event(struct acpi_ec *ec)
+static void acpi_ec_submit_query(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;
-        if (!test_and_set_bit(EC_FLAGS_EVENT_PENDING, &ec->flags)) {
-                pr_debug("***** Event query started *****\n");
+        if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
+                pr_debug("***** Event started *****\n");
                 schedule_work(&ec->work);
-                return;
-        }
-        acpi_ec_complete_request(ec);
-}
-
-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);
-                /* 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;
-        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);
 }
 
-static void acpi_ec_complete_detection(struct acpi_ec *ec)
+static void acpi_ec_complete_query(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);
+                clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
+                pr_debug("***** Event stopped *****\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;
@@ -454,7 +389,6 @@ static void 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));
@@ -465,7 +399,6 @@ static void 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;
                 }
                 goto out;
@@ -474,17 +407,16 @@ static void advance_transaction(struct acpi_ec *ec)
                     !(status & ACPI_EC_FLAG_SCI) &&
                     (t->command == ACPI_EC_COMMAND_QUERY)) {
                         t->flags |= ACPI_EC_COMMAND_POLL;
-                        acpi_ec_complete_detection(ec);
+                        acpi_ec_complete_query(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);
+                        acpi_ec_complete_query(ec);
                 } else
                         goto err;
                 goto out;
@@ -505,7 +437,7 @@ err:
         }
 out:
         if (status & ACPI_EC_FLAG_SCI)
-                acpi_ec_submit_detection(ec);
+                acpi_ec_submit_query(ec);
         if (wakeup && in_interrupt())
                 wake_up(&ec->wait);
 }
@@ -566,7 +498,7 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
         /* 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)) {
+        if (!acpi_ec_submit_flushable_request(ec)) {
                 ret = -EINVAL;
                 goto unlock;
         }
@@ -947,9 +879,7 @@ static void acpi_ec_gpe_poller(struct work_struct *work)
 {
         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,
@@ -1019,6 +949,7 @@ 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);
@@ -1169,7 +1100,7 @@ static int acpi_ec_add(struct acpi_device *device)
         ret = ec_install_handlers(ec);
 
         /* EC is fully operational, allow queries */
-        acpi_ec_enable_event(ec);
+        clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 
         /* Clear stale _Q events if hardware might require that */
         if (EC_FLAGS_CLEAR_ON_RESUME)