Better method of figuring out v1 vs v2 protocol version.

Protocol version detection isn't very reliable (especially for
hid++ v1).

Version 1 checking was potentially happening in every hidpp_device_cmd()
call and not only when requested. Improve that to do version checking
and priv->version manipulation only when requested by using
HIDPP_REFRESH_FLAGS_VERSION.

When doing version checking first try v2 protocol command and if it
succeeds assume version 2 device. Otherwise try v1 protocol query
and if that successds assume version 1 device.

v2 devices in unreachable/sleep mode seem to do not respond to v2
queries but they respond to v1 queries! Still we want best protocol
possible. To do that we are rechecking version when current protocol
version is below 2 and we are doing up_device_unifying_refresh() and if
recheck succeeds we upgrade protocol to v2.

Signed-off-by: Arkadiusz Miśkiewicz <arekm@maven.pl>
Signed-off-by: Richard Hughes <richard@hughsie.com>

2 files changed, 42 insertions, 10 deletions

diff --git a/src/linux/hidpp-device.c b/src/linux/hidpp-device.c
index bfc1b5c..5398a38 100644
--- a/src/linux/hidpp-device.c
+++ b/src/linux/hidpp-device.c
@@ -46,6 +46,7 @@
 /* HID++ 1.0 */
 #define HIDPP_READ_SHORT_REGISTER				0x81
 #define HIDPP_READ_SHORT_REGISTER_BATTERY			0x0d
+#define HIDPP_READ_SHORT_REGISTER_CONNECTION_STATE		0x02
 
 #define HIDPP_READ_LONG_REGISTER				0x83
 #define HIDPP_READ_LONG_REGISTER_DEVICE_TYPE			11
@@ -314,11 +315,6 @@ hidpp_device_cmd (HidppDevice	*device,
 	    buf[2] == HIDPP_ERR_INVALID_SUBID &&
 	    buf[3] == 0x00 &&
 	    buf[4] == HIDPP_FEATURE_ROOT_FN_PING) {
-		/* HID++ 1.0 ping reply, so fake success with version 1  */
-		if (buf[5] == HIDPP_ERROR_CODE_UNKNOWN) {
-			response_data[0] = 1;
-			goto out;
-		}
 		if (buf[5] == HIDPP_ERROR_CODE_UNSUPPORTED) {
 			/* device offline / unreachable */
 			g_set_error_literal (error, 1, 0,
@@ -533,6 +529,7 @@ hidpp_device_refresh (HidppDevice *device,
 
 	/* get version */
 	if ((refresh_flags & HIDPP_REFRESH_FLAGS_VERSION) > 0) {
+		/* first try v2 packet */
 		buf[0] = 0x00;
 		buf[1] = 0x00;
 		buf[2] = HIDPP_PING_DATA;
@@ -543,9 +540,32 @@ hidpp_device_refresh (HidppDevice *device,
 					buf, 3,
 					buf, 4,
 					error);
-		if (!ret)
-			goto out;
-		priv->version = buf[0];
+		if (ret)
+			priv->version = buf[0];
+		/* then try v1 packet */
+		else {
+			/* discard potential v1 error */
+			g_clear_error (error);
+
+			/* checking hid++ v1 packet */
+			buf[0] = 0x00;
+			buf[1] = 0x00;
+			buf[2] = 0x00;
+
+			ret = hidpp_device_cmd (device,
+					HIDPP_RECEIVER_ADDRESS,
+					HIDPP_READ_SHORT_REGISTER,
+					HIDPP_READ_SHORT_REGISTER_CONNECTION_STATE,
+					buf, 3,
+					buf, 2,
+					error);
+
+			if (!ret)
+				goto out;
+
+			priv->version = 1;
+		}
+
 	}
 
 	/* get device kind */
diff --git a/src/linux/up-device-unifying.c b/src/linux/up-device-unifying.c
index f6636e6..ea8b0b3 100644
--- a/src/linux/up-device-unifying.c
+++ b/src/linux/up-device-unifying.c
@@ -52,13 +52,25 @@ up_device_unifying_refresh (UpDevice *device)
 	gboolean ret;
 	GError *error = NULL;
 	GTimeVal timeval;
+	HidppRefreshFlags refresh_flags;
 	UpDeviceState state = UP_DEVICE_STATE_UNKNOWN;
 	UpDeviceUnifying *unifying = UP_DEVICE_UNIFYING (device);
 	UpDeviceUnifyingPrivate *priv = unifying->priv;
 
-	/* refresh just the battery stats */
+	/* refresh the battery stats */
+	refresh_flags = HIDPP_REFRESH_FLAGS_BATTERY;
+
+	/*
+	 * Device hid++ v2 when in unreachable mode seems to be able
+	 * to respond to hid++ v1 queries (but fails to respond to v2
+	 * queries). When it gets waken up it starts responding
+	 * to v2 queries, so always try to upgrade protocol to v2
+	 */
+	if (hidpp_device_get_version (priv->hidpp_device) < 2)
+		refresh_flags |= HIDPP_REFRESH_FLAGS_VERSION;
+
 	ret = hidpp_device_refresh (priv->hidpp_device,
-				    HIDPP_REFRESH_FLAGS_BATTERY,
+				    refresh_flags,
 				    &error);
 	if (!ret) {
 		g_warning ("failed to coldplug unifying device: %s",