1 files changed, 180 insertions, 133 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index a06d9837470..a66ab658abb 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1,11 +1,14 @@
 /*
- *  ec.c - ACPI Embedded Controller Driver (v2.1)
+ *  ec.c - ACPI Embedded Controller Driver (v2.2)
  *
- *  Copyright (C) 2006-2008 Alexey Starikovskiy <astarikovskiy@suse.de>
- *  Copyright (C) 2006 Denis Sadykov <denis.m.sadykov@intel.com>
- *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
- *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
- *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ *  Copyright (C) 2001-2014 Intel Corporation
+ *    Author: 2014       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>
+ *            2001, 2002 Andy Grover <andrew.grover@intel.com>
+ *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
@@ -28,6 +31,7 @@
 
 /* Uncomment next line to get verbose printout */
 /* #define DEBUG */
+#define pr_fmt(fmt) "ACPI : EC: " fmt
 
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -38,10 +42,9 @@
 #include <linux/list.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
-#include <asm/io.h>
-#include <acpi/acpi_bus.h>
-#include <acpi/acpi_drivers.h>
+#include <linux/acpi.h>
 #include <linux/dmi.h>
+#include <asm/io.h>
 
 #include "internal.h"
 
@@ -49,12 +52,10 @@
 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
 #define ACPI_EC_FILE_INFO		"info"
 
-#undef PREFIX
-#define PREFIX				"ACPI: EC: "
-
 /* EC status register */
 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
+#define ACPI_EC_FLAG_CMD	0x08	/* Input buffer contains a command */
 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
 
@@ -70,6 +71,8 @@ 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 */
@@ -79,6 +82,9 @@ enum {
 	EC_FLAGS_BLOCKED,		/* Transactions are blocked */
 };
 
+#define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
+#define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
+
 /* 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);
@@ -93,10 +99,6 @@ static unsigned int ec_storm_threshold  __read_mostly = 8;
 module_param(ec_storm_threshold, uint, 0644);
 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 
-/* If we find an EC via the ECDT, we need to keep a ptr to its context */
-/* External interfaces use first EC only, so remember */
-typedef int (*acpi_ec_query_func) (void *data);
-
 struct acpi_ec_query_handler {
 	struct list_head node;
 	acpi_ec_query_func func;
@@ -114,7 +116,7 @@ struct transaction {
 	u8 ri;
 	u8 wlen;
 	u8 rlen;
-	bool done;
+	u8 flags;
 };
 
 struct acpi_ec *boot_ec, *first_ec;
@@ -123,6 +125,7 @@ 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
@@ -131,91 +134,113 @@ static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 {
 	u8 x = inb(ec->command_addr);
-	pr_debug(PREFIX "---> status = 0x%2.2x\n", x);
+	pr_debug("EC_SC(R) = 0x%2.2x "
+		 "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d\n",
+		 x,
+		 !!(x & ACPI_EC_FLAG_SCI),
+		 !!(x & ACPI_EC_FLAG_BURST),
+		 !!(x & ACPI_EC_FLAG_CMD),
+		 !!(x & ACPI_EC_FLAG_IBF),
+		 !!(x & ACPI_EC_FLAG_OBF));
 	return x;
 }
 
 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 {
 	u8 x = inb(ec->data_addr);
-	pr_debug(PREFIX "---> data = 0x%2.2x\n", x);
+	pr_debug("EC_DATA(R) = 0x%2.2x\n", x);
 	return x;
 }
 
 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 {
-	pr_debug(PREFIX "<--- command = 0x%2.2x\n", command);
+	pr_debug("EC_SC(W) = 0x%2.2x\n", command);
 	outb(command, ec->command_addr);
 }
 
 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 {
-	pr_debug(PREFIX "<--- data = 0x%2.2x\n", data);
+	pr_debug("EC_DATA(W) = 0x%2.2x\n", data);
 	outb(data, ec->data_addr);
 }
 
-static int ec_transaction_done(struct acpi_ec *ec)
+static int ec_transaction_completed(struct acpi_ec *ec)
 {
 	unsigned long flags;
 	int ret = 0;
 	spin_lock_irqsave(&ec->lock, flags);
-	if (!ec->curr || ec->curr->done)
+	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 		ret = 1;
 	spin_unlock_irqrestore(&ec->lock, flags);
 	return ret;
 }
 
-static void start_transaction(struct acpi_ec *ec)
+static bool advance_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 advance_transaction(struct acpi_ec *ec, u8 status)
-{
-	unsigned long flags;
-	struct transaction *t = ec->curr;
+	struct transaction *t;
+	u8 status;
+	bool wakeup = false;
 
-	spin_lock_irqsave(&ec->lock, flags);
+	pr_debug("===== %s =====\n", in_interrupt() ? "IRQ" : "TASK");
+	status = acpi_ec_read_status(ec);
+	t = ec->curr;
 	if (!t)
-		goto unlock;
-	if (t->wlen > t->wi) {
-		if ((status & ACPI_EC_FLAG_IBF) == 0)
-			acpi_ec_write_data(ec,
-				t->wdata[t->wi++]);
-		else
-			goto err;
-	} else if (t->rlen > t->ri) {
-		if ((status & ACPI_EC_FLAG_OBF) == 1) {
-			t->rdata[t->ri++] = acpi_ec_read_data(ec);
-			if (t->rlen == t->ri)
-				t->done = true;
+		goto err;
+	if (t->flags & ACPI_EC_COMMAND_POLL) {
+		if (t->wlen > t->wi) {
+			if ((status & ACPI_EC_FLAG_IBF) == 0)
+				acpi_ec_write_data(ec, t->wdata[t->wi++]);
+			else
+				goto err;
+		} else if (t->rlen > t->ri) {
+			if ((status & ACPI_EC_FLAG_OBF) == 1) {
+				t->rdata[t->ri++] = acpi_ec_read_data(ec);
+				if (t->rlen == t->ri) {
+					t->flags |= ACPI_EC_COMMAND_COMPLETE;
+					wakeup = true;
+				}
+			} else
+				goto err;
+		} else if (t->wlen == t->wi &&
+			   (status & ACPI_EC_FLAG_IBF) == 0) {
+			t->flags |= ACPI_EC_COMMAND_COMPLETE;
+			wakeup = true;
+		}
+		return wakeup;
+	} else {
+		if ((status & ACPI_EC_FLAG_IBF) == 0) {
+			acpi_ec_write_cmd(ec, t->command);
+			t->flags |= ACPI_EC_COMMAND_POLL;
 		} else
 			goto err;
-	} else if (t->wlen == t->wi &&
-		   (status & ACPI_EC_FLAG_IBF) == 0)
-		t->done = true;
-	goto unlock;
+		return wakeup;
+	}
 err:
 	/*
 	 * If SCI bit is set, then don't think it's a false IRQ
 	 * otherwise will take a not handled IRQ as a false one.
 	 */
-	if (in_interrupt() && !(status & ACPI_EC_FLAG_SCI))
-		++t->irq_count;
+	if (!(status & ACPI_EC_FLAG_SCI)) {
+		if (in_interrupt() && t)
+			++t->irq_count;
+	}
+	return wakeup;
+}
 
-unlock:
-	spin_unlock_irqrestore(&ec->lock, flags);
+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);
+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);
+			return acpi_ec_sync_query(ec, NULL);
 	}
 	return 0;
 }
@@ -231,17 +256,19 @@ static int ec_poll(struct acpi_ec *ec)
 			/* don't sleep with disabled interrupts */
 			if (EC_FLAGS_MSI || irqs_disabled()) {
 				udelay(ACPI_EC_MSI_UDELAY);
-				if (ec_transaction_done(ec))
+				if (ec_transaction_completed(ec))
 					return 0;
 			} else {
 				if (wait_event_timeout(ec->wait,
-						ec_transaction_done(ec),
+						ec_transaction_completed(ec),
 						msecs_to_jiffies(1)))
 					return 0;
 			}
-			advance_transaction(ec, acpi_ec_read_status(ec));
+			spin_lock_irqsave(&ec->lock, flags);
+			(void)advance_transaction(ec);
+			spin_unlock_irqrestore(&ec->lock, flags);
 		} while (time_before(jiffies, delay));
-		pr_debug(PREFIX "controller reset, restart transaction\n");
+		pr_debug("controller reset, restart transaction\n");
 		spin_lock_irqsave(&ec->lock, flags);
 		start_transaction(ec);
 		spin_unlock_irqrestore(&ec->lock, flags);
@@ -271,23 +298,6 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 	return ret;
 }
 
-static int ec_check_ibf0(struct acpi_ec *ec)
-{
-	u8 status = acpi_ec_read_status(ec);
-	return (status & ACPI_EC_FLAG_IBF) == 0;
-}
-
-static int ec_wait_ibf0(struct acpi_ec *ec)
-{
-	unsigned long delay = jiffies + msecs_to_jiffies(ec_delay);
-	/* interrupt wait manually if GPE mode is not active */
-	while (time_before(jiffies, delay))
-		if (wait_event_timeout(ec->wait, ec_check_ibf0(ec),
-					msecs_to_jiffies(1)))
-			return 0;
-	return -ETIME;
-}
-
 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 {
 	int status;
@@ -308,13 +318,7 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 			goto unlock;
 		}
 	}
-	if (ec_wait_ibf0(ec)) {
-		pr_err(PREFIX "input buffer is not empty, "
-				"aborting transaction\n");
-		status = -ETIME;
-		goto end;
-	}
-	pr_debug(PREFIX "transaction start (cmd=0x%02x, addr=0x%02x)\n",
+	pr_debug("transaction start (cmd=0x%02x, addr=0x%02x)\n",
 			t->command, t->wdata ? t->wdata[0] : 0);
 	/* disable GPE during transaction if storm is detected */
 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
@@ -331,13 +335,12 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 		/* 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(PREFIX "GPE storm detected(%d GPEs), "
+		pr_info("GPE storm detected(%d GPEs), "
 			"transactions will use polling mode\n",
 			t->irq_count);
 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
 	}
-	pr_debug(PREFIX "transaction end\n");
-end:
+	pr_debug("transaction end\n");
 	if (ec->global_lock)
 		acpi_release_global_lock(glk);
 unlock:
@@ -388,27 +391,6 @@ static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 	return acpi_ec_transaction(ec, &t);
 }
 
-/*
- * Externally callable EC access functions. For now, assume 1 EC only
- */
-int ec_burst_enable(void)
-{
-	if (!first_ec)
-		return -ENODEV;
-	return acpi_ec_burst_enable(first_ec);
-}
-
-EXPORT_SYMBOL(ec_burst_enable);
-
-int ec_burst_disable(void)
-{
-	if (!first_ec)
-		return -ENODEV;
-	return acpi_ec_burst_disable(first_ec);
-}
-
-EXPORT_SYMBOL(ec_burst_disable);
-
 int ec_read(u8 addr, u8 *val)
 {
 	int err;
@@ -467,6 +449,27 @@ acpi_handle ec_get_handle(void)
 
 EXPORT_SYMBOL(ec_get_handle);
 
+/*
+ * Process _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_sync_query(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;
@@ -490,6 +493,10 @@ 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);
 }
 
@@ -570,22 +577,27 @@ static void acpi_ec_run(void *cxt)
 	struct acpi_ec_query_handler *handler = cxt;
 	if (!handler)
 		return;
-	pr_debug(PREFIX "start query execution\n");
+	pr_debug("start query execution\n");
 	if (handler->func)
 		handler->func(handler->data);
 	else if (handler->handle)
 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
-	pr_debug(PREFIX "stop query execution\n");
+	pr_debug("stop query execution\n");
 	kfree(handler);
 }
 
-static int acpi_ec_sync_query(struct acpi_ec *ec)
+static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data)
 {
 	u8 value = 0;
 	int status;
 	struct acpi_ec_query_handler *handler, *copy;
-	if ((status = acpi_ec_query_unlocked(ec, &value)))
+
+	status = acpi_ec_query_unlocked(ec, &value);
+	if (data)
+		*data = value;
+	if (status)
 		return status;
+
 	list_for_each_entry(handler, &ec->list, node) {
 		if (value == handler->query_bit) {
 			/* have custom handler for this bit */
@@ -593,7 +605,8 @@ static int acpi_ec_sync_query(struct acpi_ec *ec)
 			if (!copy)
 				return -ENOMEM;
 			memcpy(copy, handler, sizeof(*copy));
-			pr_debug(PREFIX "push query execution (0x%2x) on queue\n", value);
+			pr_debug("push query execution (0x%2x) on queue\n",
+				value);
 			return acpi_os_execute((copy->func) ?
 				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
 				acpi_ec_run, copy);
@@ -608,7 +621,7 @@ static void acpi_ec_gpe_query(void *ec_cxt)
 	if (!ec)
 		return;
 	mutex_lock(&ec->mutex);
-	acpi_ec_sync_query(ec);
+	acpi_ec_sync_query(ec, NULL);
 	mutex_unlock(&ec->mutex);
 }
 
@@ -616,7 +629,7 @@ static int ec_check_sci(struct acpi_ec *ec, u8 state)
 {
 	if (state & ACPI_EC_FLAG_SCI) {
 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
-			pr_debug(PREFIX "push gpe query to the queue\n");
+			pr_debug("push gpe query to the queue\n");
 			return acpi_os_execute(OSL_NOTIFY_HANDLER,
 				acpi_ec_gpe_query, ec);
 		}
@@ -627,17 +640,14 @@ static int ec_check_sci(struct acpi_ec *ec, u8 state)
 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
 	u32 gpe_number, void *data)
 {
+	unsigned long flags;
 	struct acpi_ec *ec = data;
-	u8 status = acpi_ec_read_status(ec);
-
-	pr_debug(PREFIX "~~~> interrupt, status:0x%02x\n", status);
 
-	advance_transaction(ec, status);
-	if (ec_transaction_done(ec) &&
-	    (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
+	spin_lock_irqsave(&ec->lock, flags);
+	if (advance_transaction(ec))
 		wake_up(&ec->wait);
-		ec_check_sci(ec, acpi_ec_read_status(ec));
-	}
+	spin_unlock_irqrestore(&ec->lock, flags);
+	ec_check_sci(ec, acpi_ec_read_status(ec));
 	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
 }
 
@@ -776,12 +786,12 @@ static int ec_install_handlers(struct acpi_ec *ec)
 			 * The AE_NOT_FOUND error will be ignored and OS
 			 * continue to initialize EC.
 			 */
-			printk(KERN_ERR "Fail in evaluating the _REG object"
+			pr_err("Fail in evaluating the _REG object"
 				" of EC device. Broken bios is suspected.\n");
 		} else {
+			acpi_disable_gpe(NULL, ec->gpe);
 			acpi_remove_gpe_handler(NULL, ec->gpe,
 				&acpi_ec_gpe_handler);
-			acpi_disable_gpe(NULL, ec->gpe);
 			return -ENODEV;
 		}
 	}
@@ -795,10 +805,10 @@ static void ec_remove_handlers(struct acpi_ec *ec)
 	acpi_disable_gpe(NULL, ec->gpe);
 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
-		pr_err(PREFIX "failed to remove space handler\n");
+		pr_err("failed to remove space handler\n");
 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
 				&acpi_ec_gpe_handler)))
-		pr_err(PREFIX "failed to remove gpe handler\n");
+		pr_err("failed to remove gpe handler\n");
 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
 }
 
@@ -840,13 +850,20 @@ static int acpi_ec_add(struct acpi_device *device)
 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
 
-	pr_info(PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
+	pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
 			  ec->gpe, ec->command_addr, ec->data_addr);
 
 	ret = ec_install_handlers(ec);
 
 	/* 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;
 }
 
@@ -931,7 +948,7 @@ static int ec_validate_ecdt(const struct dmi_system_id *id)
 /* MSI EC needs special treatment, enable it */
 static int ec_flag_msi(const struct dmi_system_id *id)
 {
-	printk(KERN_DEBUG PREFIX "Detected MSI hardware, enabling workarounds.\n");
+	pr_debug("Detected MSI hardware, enabling workarounds.\n");
 	EC_FLAGS_MSI = 1;
 	EC_FLAGS_VALIDATE_ECDT = 1;
 	return 0;
@@ -948,6 +965,30 @@ 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", {
@@ -991,6 +1032,9 @@ 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},
 	{},
 };
 
@@ -1010,7 +1054,7 @@ int __init acpi_ec_ecdt_probe(void)
 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
 				(struct acpi_table_header **)&ecdt_ptr);
 	if (ACPI_SUCCESS(status)) {
-		pr_info(PREFIX "EC description table is found, configuring boot EC\n");
+		pr_info("EC description table is found, configuring boot EC\n");
 		boot_ec->command_addr = ecdt_ptr->control.address;
 		boot_ec->data_addr = ecdt_ptr->data.address;
 		boot_ec->gpe = ecdt_ptr->gpe;
@@ -1025,12 +1069,14 @@ int __init acpi_ec_ecdt_probe(void)
 	/* fall through */
 	}
 
-	if (EC_FLAGS_SKIP_DSDT_SCAN)
+	if (EC_FLAGS_SKIP_DSDT_SCAN) {
+		kfree(saved_ec);
 		return -ENODEV;
+	}
 
 	/* This workaround is needed only on some broken machines,
 	 * which require early EC, but fail to provide ECDT */
-	printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
+	pr_debug("Look up EC in DSDT\n");
 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
 					boot_ec, NULL);
 	/* Check that acpi_get_devices actually find something */
@@ -1042,7 +1088,7 @@ int __init acpi_ec_ecdt_probe(void)
 		    saved_ec->data_addr != boot_ec->data_addr ||
 		    saved_ec->gpe != boot_ec->gpe ||
 		    saved_ec->handle != boot_ec->handle)
-			pr_info(PREFIX "ASUSTek keeps feeding us with broken "
+			pr_info("ASUSTek keeps feeding us with broken "
 			"ECDT tables, which are very hard to workaround. "
 			"Trying to use DSDT EC info instead. Please send "
 			"output of acpidump to linux-acpi@vger.kernel.org\n");
@@ -1064,6 +1110,7 @@ install:
 	}
 error:
 	kfree(boot_ec);
+	kfree(saved_ec);
 	boot_ec = NULL;
 	return -ENODEV;
 }