Merge branches 'acpi-scan' and 'acpi-ec'

* acpi-scan:
  ACPI: Use ACPI companion to match only the first physical device

* acpi-ec:
  ACPI / EC: Fix regression due to conflicting firmware behavior between Samsung and Acer.
  Revert "ACPI / EC: Add support to disallow QR_EC to be issued before completing previous QR_EC"

drivers/acpi/ec.c

@@ -126,6 +126,7 @@ 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 */
+static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 
 /* --------------------------------------------------------------------------
  *                           Transaction Management
@@ -236,13 +237,8 @@ static bool advance_transaction(struct acpi_ec *ec)
 		}
 		return wakeup;
 	} else {
-		/*
-		 * There is firmware refusing to respond QR_EC when SCI_EVT
-		 * is not set, for which case, we complete the QR_EC
-		 * without issuing it to the firmware.
-		 * https://bugzilla.kernel.org/show_bug.cgi?id=86211
-		 */
-		if (!(status & ACPI_EC_FLAG_SCI) &&
+		if (EC_FLAGS_QUERY_HANDSHAKE &&
+		    !(status & ACPI_EC_FLAG_SCI) &&
 		    (t->command == ACPI_EC_COMMAND_QUERY)) {
 			t->flags |= ACPI_EC_COMMAND_POLL;
 			t->rdata[t->ri++] = 0x00;
@@ -334,13 +330,13 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 	pr_debug("***** Command(%s) started *****\n",
 		 acpi_ec_cmd_string(t->command));
 	start_transaction(ec);
-	spin_unlock_irqrestore(&ec->lock, tmp);
-	ret = ec_poll(ec);
-	spin_lock_irqsave(&ec->lock, tmp);
 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 		pr_debug("***** Event stopped *****\n");
 	}
+	spin_unlock_irqrestore(&ec->lock, tmp);
+	ret = ec_poll(ec);
+	spin_lock_irqsave(&ec->lock, tmp);
 	pr_debug("***** Command(%s) stopped *****\n",
 		 acpi_ec_cmd_string(t->command));
 	ec->curr = NULL;
@@ -1011,6 +1007,18 @@ static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
 	return 0;
 }
 
+/*
+ * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for
+ * which case, we complete the QR_EC without issuing it to the firmware.
+ * https://bugzilla.kernel.org/show_bug.cgi?id=86211
+ */
+static int ec_flag_query_handshake(const struct dmi_system_id *id)
+{
+	pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
+	EC_FLAGS_QUERY_HANDSHAKE = 1;
+	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
@@ -1085,6 +1093,9 @@ static struct dmi_system_id ec_dmi_table[] __initdata = {
 	{
 	ec_clear_on_resume, "Samsung hardware", {
 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
+	{
+	ec_flag_query_handshake, "Acer hardware", {
+	DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL},
 	{},
 };
 

drivers/acpi/scan.c

@@ -141,6 +141,53 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
 	return len;
 }
 
+/*
+ * acpi_companion_match() - Can we match via ACPI companion device
+ * @dev: Device in question
+ *
+ * Check if the given device has an ACPI companion and if that companion has
+ * a valid list of PNP IDs, and if the device is the first (primary) physical
+ * device associated with it.
+ *
+ * If multiple physical devices are attached to a single ACPI companion, we need
+ * to be careful.  The usage scenario for this kind of relationship is that all
+ * of the physical devices in question use resources provided by the ACPI
+ * companion.  A typical case is an MFD device where all the sub-devices share
+ * the parent's ACPI companion.  In such cases we can only allow the primary
+ * (first) physical device to be matched with the help of the companion's PNP
+ * IDs.
+ *
+ * Additional physical devices sharing the ACPI companion can still use
+ * resources available from it but they will be matched normally using functions
+ * provided by their bus types (and analogously for their modalias).
+ */
+static bool acpi_companion_match(const struct device *dev)
+{
+	struct acpi_device *adev;
+	bool ret;
+
+	adev = ACPI_COMPANION(dev);
+	if (!adev)
+		return false;
+
+	if (list_empty(&adev->pnp.ids))
+		return false;
+
+	mutex_lock(&adev->physical_node_lock);
+	if (list_empty(&adev->physical_node_list)) {
+		ret = false;
+	} else {
+		const struct acpi_device_physical_node *node;
+
+		node = list_first_entry(&adev->physical_node_list,
+					struct acpi_device_physical_node, node);
+		ret = node->dev == dev;
+	}
+	mutex_unlock(&adev->physical_node_lock);
+
+	return ret;
+}
+
 /*
  * Creates uevent modalias field for ACPI enumerated devices.
  * Because the other buses does not support ACPI HIDs & CIDs.
@@ -149,20 +196,14 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
  */
 int acpi_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
 {
-	struct acpi_device *acpi_dev;
 	int len;
 
-	acpi_dev = ACPI_COMPANION(dev);
-	if (!acpi_dev)
-		return -ENODEV;
-
-	/* Fall back to bus specific way of modalias exporting */
-	if (list_empty(&acpi_dev->pnp.ids))
+	if (!acpi_companion_match(dev))
 		return -ENODEV;
 
 	if (add_uevent_var(env, "MODALIAS="))
 		return -ENOMEM;
-	len = create_modalias(acpi_dev, &env->buf[env->buflen - 1],
+	len = create_modalias(ACPI_COMPANION(dev), &env->buf[env->buflen - 1],
 				sizeof(env->buf) - env->buflen);
 	if (len <= 0)
 		return len;
@@ -179,18 +220,12 @@ EXPORT_SYMBOL_GPL(acpi_device_uevent_modalias);
  */
 int acpi_device_modalias(struct device *dev, char *buf, int size)
 {
-	struct acpi_device *acpi_dev;
 	int len;
 
-	acpi_dev = ACPI_COMPANION(dev);
-	if (!acpi_dev)
+	if (!acpi_companion_match(dev))
 		return -ENODEV;
 
-	/* Fall back to bus specific way of modalias exporting */
-	if (list_empty(&acpi_dev->pnp.ids))
-		return -ENODEV;
-
-	len = create_modalias(acpi_dev, buf, size -1);
+	len = create_modalias(ACPI_COMPANION(dev), buf, size -1);
 	if (len <= 0)
 		return len;
 	buf[len++] = '\n';
@@ -853,6 +888,9 @@ const struct acpi_device_id *acpi_match_device(const struct acpi_device_id *ids,
 	if (!ids || !handle || acpi_bus_get_device(handle, &adev))
 		return NULL;
 
+	if (!acpi_companion_match(dev))
+		return NULL;
+
 	return __acpi_match_device(adev, ids);
 }
 EXPORT_SYMBOL_GPL(acpi_match_device);