[PATCH] HID: sony: Fix for broken buttons on DS3 USB dongles

[scott.shumate@gmail.com]

Fix for non-working buttons on knock-off USB dongles for Sony
controllers. These USB dongles are used to connect older Sony DA/DS1/DS2
controllers via USB and are common on Amazon, AliExpress, etc.  Without
the patch, the square, X, and circle buttons do not function.  These
dongles used to work prior to kernel 4.10 but removing the global DS3
report fixup in this commit exposed the problem:

commit e19a267b9987 Author: Roderick Colenbrander
 <roderick.colenbrander@sony.com>
Date:   Tue Mar 7 15:45:08 2017 -0800

    HID: sony: DS3 comply to Linux gamepad spec

Many people reported the problem on the Ubuntu forums and are working
around the problem by falling back to the 4.9 hid-sony driver.

The problem stems from these dongles incorrectly reporting their button
count as 13 instead of 16.  This patch fixes up the report descriptor by
changing the button report count to 16 and removing 3 padding bits.

Signed-off-by: Scott Shumate <scott.shumate@gmail.com>
---
diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
index 4c6ed6ef31f1..2f073f536070 100644
--- a/drivers/hid/hid-sony.c
+++ b/drivers/hid/hid-sony.c
@@ -867,6 +867,23 @@ static u8 *sony_report_fixup(struct hid_device *hdev, u8 *rdesc,
 	if (sc->quirks & PS3REMOTE)
 		return ps3remote_fixup(hdev, rdesc, rsize);
 
+	/*
+	 * Some knock-off USB dongles incorrectly report their button count
+	 * as 13 instead of 16 causing three non-functional buttons.
+	 */
+	if ((sc->quirks & SIXAXIS_CONTROLLER_USB) && *rsize >= 45 &&
+		/* Report Count (13) */
+		rdesc[23] == 0x95 && rdesc[24] == 0x0D &&
+		/* Usage Maximum (13) */
+		rdesc[37] == 0x29 && rdesc[38] == 0x0D &&
+		/* Report Count (3) */
+		rdesc[43] == 0x95 && rdesc[44] == 0x03) {
+		hid_info(hdev, "Fixing up USB dongle report descriptor\n");
+		rdesc[24] = 0x10;
+		rdesc[38] = 0x10;
+		rdesc[44] = 0x00;
+	}
+
 	return rdesc;
 }