[PATCH v2] dell-wmi: Update code for processing WMI events

["Pali Rohár" <pali.rohar@gmail.com>]

WMI buffer can contains more events. First value in buffer is length of event
followed by data of specified length. After that is next length and next data.
When length is zero then there is no more events in bufffer.

This patch adds support for processing all events in buffer (not only first)
and parse more event types (not only hotkey events). Because of variable length
of events sometimes BIOS fills more hotkeys (or other values) into single WMI
event. In this case this patch process also these multiple hotkeys (and not
only first one).

Some event types are just ignored because kernel is not interested for them
(e.g. NIC Link status, battery unplug, ...).

This patch is based on DSDT table from Dell Latitude E6440. Code should be
backward compatible so will process other events of old types same as before
this patch.

This patch also fixes problem when in kernel log are written messages about
unknown WMI events. Now all know events are parsed and those which are not
interesting for kernel are dropped without unknown message.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Tested-by: Pali Rohár <pali.rohar@gmail.com>
---
Changes since v1:
* change some pr_info calls with pr_warn
* fix coding style
---
 drivers/platform/x86/dell-wmi.c |  159 +++++++++++++++++++++++++++++++--------
 1 file changed, 128 insertions(+), 31 deletions(-)

diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index 25721bf..e2b6a64 100644
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -145,57 +145,154 @@ static const u16 bios_to_linux_keycode[256] __initconst = {
 
 static struct input_dev *dell_wmi_input_dev;
 
+static void dell_wmi_process_key(int reported_key)
+{
+	const struct key_entry *key;
+
+	key = sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
+						reported_key);
+	if (!key) {
+		pr_info("Unknown key %x pressed\n", reported_key);
+		return;
+	}
+
+	pr_debug("Key %x pressed\n", reported_key);
+
+	/* Don't report brightness notifications that will also come via ACPI */
+	if ((key->keycode == KEY_BRIGHTNESSUP ||
+	     key->keycode == KEY_BRIGHTNESSDOWN) && acpi_video)
+		return;
+
+	sparse_keymap_report_entry(dell_wmi_input_dev, key, 1, true);
+}
+
 static void dell_wmi_notify(u32 value, void *context)
 {
 	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
 	union acpi_object *obj;
 	acpi_status status;
+	acpi_size buffer_size;
+	u16 *buffer_entry, *buffer_end;
+	int len, i;
 
 	status = wmi_get_event_data(value, &response);
 	if (status != AE_OK) {
-		pr_info("bad event status 0x%x\n", status);
+		pr_warn("bad event status 0x%x\n", status);
 		return;
 	}
 
 	obj = (union acpi_object *)response.pointer;
+	if (!obj) {
+		pr_warn("no response\n");
+		return;
+	}
 
-	if (obj && obj->type == ACPI_TYPE_BUFFER) {
-		const struct key_entry *key;
-		int reported_key;
-		u16 *buffer_entry = (u16 *)obj->buffer.pointer;
-		int buffer_size = obj->buffer.length/2;
-
-		if (buffer_size >= 2 && dell_new_hk_type && buffer_entry[1] != 0x10) {
-			pr_info("Received unknown WMI event (0x%x)\n",
-				buffer_entry[1]);
-			kfree(obj);
-			return;
-		}
+	if (obj->type != ACPI_TYPE_BUFFER) {
+		pr_warn("bad response type %x\n", obj->type);
+		kfree(obj);
+		return;
+	}
+
+	pr_debug("Received WMI event (%*ph)\n",
+		obj->buffer.length, obj->buffer.pointer);
 
-		if (buffer_size >= 3 && (dell_new_hk_type || buffer_entry[1] == 0x0))
-			reported_key = (int)buffer_entry[2];
+	buffer_entry = (u16 *)obj->buffer.pointer;
+	buffer_size = obj->buffer.length/2;
+
+	if (!dell_new_hk_type) {
+		if (buffer_size >= 3 && buffer_entry[1] == 0x0)
+			dell_wmi_process_key(buffer_entry[2]);
 		else if (buffer_size >= 2)
-			reported_key = (int)buffer_entry[1] & 0xffff;
-		else {
+			dell_wmi_process_key(buffer_entry[1]);
+		else
 			pr_info("Received unknown WMI event\n");
-			kfree(obj);
-			return;
+		kfree(obj);
+		return;
+	}
+
+	buffer_end = buffer_entry + buffer_size;
+
+	while (buffer_entry < buffer_end) {
+
+		len = buffer_entry[0];
+		if (len == 0)
+			break;
+
+		len++;
+
+		if (buffer_entry + len > buffer_end) {
+			pr_warn("Invalid length of WMI event\n");
+			break;
 		}
 
-		key = sparse_keymap_entry_from_scancode(dell_wmi_input_dev,
-							reported_key);
-		if (!key) {
-			pr_info("Unknown key %x pressed\n", reported_key);
-		} else if ((key->keycode == KEY_BRIGHTNESSUP ||
-			    key->keycode == KEY_BRIGHTNESSDOWN) && acpi_video) {
-			/* Don't report brightness notifications that will also
-			 * come via ACPI */
-			;
-		} else {
-			sparse_keymap_report_entry(dell_wmi_input_dev, key,
-						   1, true);
+		pr_debug("Process buffer (%*ph)\n", len*2, buffer_entry);
+
+		switch (buffer_entry[1]) {
+		case 0x00:
+			for (i = 2; i < len; ++i) {
+				switch (buffer_entry[i]) {
+				case 0xe043:
+					/* NIC Link is Up */
+					pr_debug("NIC Link is Up\n");
+					break;
+				case 0xe044:
+					/* NIC Link is Down */
+					pr_debug("NIC Link is Down\n");
+					break;
+				case 0xe045:
+					/* Unknown event but defined in DSDT */
+				default:
+					/* Unknown event */
+					pr_info("Unknown WMI event type 0x00: "
+						"0x%x\n", (int)buffer_entry[i]);
+					break;
+				}
+			}
+			break;
+		case 0x10:
+			/* Keys pressed */
+			for (i = 2; i < len; ++i)
+				dell_wmi_process_key(buffer_entry[i]);
+			break;
+		case 0x11:
+			for (i = 2; i < len; ++i) {
+				switch (buffer_entry[i]) {
+				case 0xfff0:
+					/* Battery unplugged */
+					pr_debug("Battery unplugged\n");
+					break;
+				case 0xfff1:
+					/* Battery inserted */
+					pr_debug("Battery inserted\n");
+					break;
+				case 0x01e1:
+				case 0x02ea:
+				case 0x02eb:
+				case 0x02ec:
+				case 0x02f6:
+					/* Keyboard backlight level changed */
+					pr_debug("Keyboard backlight level "
+						 "changed\n");
+					break;
+				default:
+					/* Unknown event */
+					pr_info("Unknown WMI event type 0x11: "
+						"0x%x\n", (int)buffer_entry[i]);
+					break;
+				}
+			}
+			break;
+		default:
+			/* Unknown event */
+			pr_info("Unknown WMI event type 0x%x\n",
+				(int)buffer_entry[1]);
+			break;
 		}
+
+		buffer_entry += len;
+
 	}
+
 	kfree(obj);
 }
 
-- 
1.7.9.5