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[v12,09/14] HID: nintendo: patch hw version for userspace HID mappings

Message ID 20200823044157.339677-10-djogorchock@gmail.com
State New
Delegated to: Jiri Kosina
Headers show
Series HID: nintendo | expand

Commit Message

Daniel Ogorchock Aug. 23, 2020, 4:41 a.m. UTC
This patch sets the most significant bit of the hid hw version to allow
userspace to distinguish between this driver's input mappings vs. the
default hid mappings. This prevents breaking userspace applications that
use SDL2 for gamepad input, allowing them to distinguish the mappings
based on the version.

Signed-off-by: Daniel J. Ogorchock <djogorchock@gmail.com>
 drivers/hid/hid-nintendo.c | 9 +++++++++
 1 file changed, 9 insertions(+)
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diff --git a/drivers/hid/hid-nintendo.c b/drivers/hid/hid-nintendo.c
index f2864fd9fc5d..c2f7dc83d875 100644
--- a/drivers/hid/hid-nintendo.c
+++ b/drivers/hid/hid-nintendo.c
@@ -1423,6 +1423,15 @@  static int nintendo_hid_probe(struct hid_device *hdev,
 		goto err_wq;
+	/*
+	 * Patch the hw version of pro controller/joycons, so applications can
+	 * distinguish between the default HID mappings and the mappings defined
+	 * by the Linux game controller spec. This is important for the SDL2
+	 * library, which has a game controller database, which uses device ids
+	 * in combination with version as a key.
+	 */
+	hdev->version |= 0x8000;
 	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
 	if (ret) {
 		hid_err(hdev, "HW start failed\n");