Merge remote-tracking branch 'spi/topic/core' into spi-next

[cascardo/linux.git] / drivers / acpi / ec.c

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 959d41a..d7d32c2 100644 (file)
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -67,6 +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 */
@@ -116,6 +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
@@ -440,6 +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;
@@ -463,6 +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);
 }
 
@@ -821,6 +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;
 }
 
@@ -922,6 +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", {
@@ -965,6 +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},
        {},
 };