1 files changed, 67 insertions, 29 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index ba5b56db9d27..d7d32c28829b 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -39,10 +39,9 @@
 #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"
 
@@ -68,6 +67,8 @@ 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 */
@@ -91,10 +92,6 @@ 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;
@@ -121,6 +118,7 @@ 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
@@ -387,27 +385,6 @@ 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;
@@ -466,6 +443,29 @@ acpi_handle ec_get_handle(void)
 
 EXPORT_SYMBOL(ec_get_handle);
 
+static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 *data);
+
+/*
+ * Clears stale _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_query_unlocked(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;
@@ -489,6 +489,10 @@ 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);
 }
 
@@ -779,9 +783,9 @@ 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_remove_gpe_handler(NULL, ec->gpe,
                                 &acpi_ec_gpe_handler);
-                        acpi_disable_gpe(NULL, ec->gpe);
                         return -ENODEV;
                 }
         }
@@ -847,6 +851,13 @@ static int acpi_ec_add(struct acpi_device *device)
 
         /* 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;
 }
 
@@ -948,6 +959,30 @@ 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 +1026,9 @@ 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},
         {},
 };