ACPI: EC: restart failed command

Restart current transaction if we recieved unexpected GPEs instead
of needed ones.

http://bugzilla.kernel.org/show_bug.cgi?id=11896

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 29 insertions, 12 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index cebd65d2e2a9..34c67ca3bebe 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -100,6 +100,8 @@ struct transaction {
         u8 *rdata;
         unsigned short irq_count;
         u8 command;
+        u8 wi;
+        u8 ri;
         u8 wlen;
         u8 rlen;
         bool done;
@@ -185,26 +187,34 @@ static int ec_transaction_done(struct acpi_ec *ec)
         return ret;
 }
 
+static void start_transaction(struct acpi_ec *ec)
+{
+        ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
+        ec->curr->done = false;
+        acpi_ec_write_cmd(ec, ec->curr->command);
+}
+
 static void gpe_transaction(struct acpi_ec *ec, u8 status)
 {
         unsigned long flags;
         spin_lock_irqsave(&ec->curr_lock, flags);
         if (!ec->curr)
                 goto unlock;
-        if (ec->curr->wlen > 0) {
-                if ((status & ACPI_EC_FLAG_IBF) == 0) {
-                        acpi_ec_write_data(ec, *(ec->curr->wdata++));
-                        --ec->curr->wlen;
-                } else
+        if (ec->curr->wlen > ec->curr->wi) {
+                if ((status & ACPI_EC_FLAG_IBF) == 0)
+                        acpi_ec_write_data(ec,
+                                ec->curr->wdata[ec->curr->wi++]);
+                else
                         goto err;
-        } else if (ec->curr->rlen > 0) {
+        } else if (ec->curr->rlen > ec->curr->ri) {
                 if ((status & ACPI_EC_FLAG_OBF) == 1) {
-                        *(ec->curr->rdata++) = acpi_ec_read_data(ec);
-                        if (--ec->curr->rlen == 0)
+                        ec->curr->rdata[ec->curr->ri++] = acpi_ec_read_data(ec);
+                        if (ec->curr->rlen == ec->curr->ri)
                                 ec->curr->done = true;
                 } else
                         goto err;
-        } else if (ec->curr->wlen == 0 && (status & ACPI_EC_FLAG_IBF) == 0)
+        } else if (ec->curr->wlen == ec->curr->wi &&
+                   (status & ACPI_EC_FLAG_IBF) == 0)
                 ec->curr->done = true;
         goto unlock;
 err:
@@ -219,6 +229,15 @@ static int acpi_ec_wait(struct acpi_ec *ec)
         if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
                                msecs_to_jiffies(ACPI_EC_DELAY)))
                 return 0;
+        /* try restart command if we get any false interrupts */
+        if (ec->curr->irq_count &&
+            (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
+                pr_debug(PREFIX "controller reset, restart transaction\n");
+                start_transaction(ec);
+                if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
+                                        msecs_to_jiffies(ACPI_EC_DELAY)))
+                        return 0;
+        }
         /* missing GPEs, switch back to poll mode */
         if (printk_ratelimit())
                 pr_info(PREFIX "missing confirmations, "
@@ -268,10 +287,8 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
         /* start transaction */
         spin_lock_irqsave(&ec->curr_lock, tmp);
         /* following two actions should be kept atomic */
-        t->irq_count = 0;
-        t->done = false;
         ec->curr = t;
-        acpi_ec_write_cmd(ec, ec->curr->command);
+        start_transaction(ec);
         if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
         spin_unlock_irqrestore(&ec->curr_lock, tmp);