Patch "Input: xpad - fix PowerA init quirk for some gamepad models" has been added to the 4.12-stable tree

This is a note to let you know that I've just added the patch titled

Input: xpad - fix PowerA init quirk for some gamepad models

to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
input-xpad-fix-powera-init-quirk-for-some-gamepad-models.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Cameron Gutman <[email protected]>
Date: Thu, 31 Aug 2017 11:52:20 -0700
Subject: Input: xpad - fix PowerA init quirk for some gamepad models

From: Cameron Gutman <[email protected]>

commit f5308d1b83eba20e69df5e0926ba7257c8dd9074 upstream.

The PowerA gamepad initialization quirk worked with the PowerA wired gamepad I had around (0x24c6:0x543a), but a user reported [0] that it didn't work for him, even though our gamepads shared the same vendor and product IDs.

When I initially implemented the PowerA quirk, I wanted to avoid actually triggering the rumble action during init. My tests showed that my gamepad would work correctly even if it received a rumble of 0 intensity, so that's what I went with.

Unfortunately, this apparently isn't true for all models (perhaps a firmware difference?). This non-working gamepad seems to require the real magic rumble packet that the Microsoft driver sends, which actually vibrates the gamepad. To counteract this effect, I still send the old zero-rumble PowerA quirk packet which cancels the rumble effect before the motors can spin up enough to vibrate.

[0]: https://github.com/paroj/xpad/issues/48#issuecomment-313904867

---
 drivers/input/joystick/xpad.c |   24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

@@ -389,10 +389,21 @@ static const u8 xboxone_hori_init[] = {
 };
 
 /*
- * A rumble packet is required for some PowerA pads to start
+ * A specific rumble packet is required for some PowerA pads to start
  * sending input reports. One of those pads is (0x24c6:0x543a).
  */
-static const u8 xboxone_zerorumble_init[] = {
+static const u8 xboxone_rumblebegin_init[] = {
+	0x09, 0x00, 0x00, 0x09, 0x00, 0x0F, 0x00, 0x00,
+	0x1D, 0x1D, 0xFF, 0x00, 0x00
+};
+
+/*
+ * A rumble packet with zero FF intensity will immediately
+ * terminate the rumbling required to init PowerA pads.
+ * This should happen fast enough that the motors don't
+ * spin up to enough speed to actually vibrate the gamepad.
+ */
+static const u8 xboxone_rumbleend_init[] = {
 	0x09, 0x00, 0x00, 0x09, 0x00, 0x0F, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00
 };

@@ -407,9 +418,12 @@ static const struct xboxone_init_packet
 	XBOXONE_INIT_PKT(0x0e6f, 0x0165, xboxone_hori_init),
 	XBOXONE_INIT_PKT(0x0f0d, 0x0067, xboxone_hori_init),
 	XBOXONE_INIT_PKT(0x0000, 0x0000, xboxone_fw2015_init),
-	XBOXONE_INIT_PKT(0x24c6, 0x541a, xboxone_zerorumble_init),
-	XBOXONE_INIT_PKT(0x24c6, 0x542a, xboxone_zerorumble_init),
-	XBOXONE_INIT_PKT(0x24c6, 0x543a, xboxone_zerorumble_init),
+	XBOXONE_INIT_PKT(0x24c6, 0x541a, xboxone_rumblebegin_init),
+	XBOXONE_INIT_PKT(0x24c6, 0x542a, xboxone_rumblebegin_init),
+	XBOXONE_INIT_PKT(0x24c6, 0x543a, xboxone_rumblebegin_init),
+	XBOXONE_INIT_PKT(0x24c6, 0x541a, xboxone_rumbleend_init),
+	XBOXONE_INIT_PKT(0x24c6, 0x542a, xboxone_rumbleend_init),
+	XBOXONE_INIT_PKT(0x24c6, 0x543a, xboxone_rumbleend_init),
 };
 
 struct xpad_output_packet {

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/input-xpad-fix-powera-init-quirk-for-some-gamepad-models.patch