From: Antheas Kapenekakis lkml@antheas.dev
[ Upstream commit 1f3214aae9f49faf495f3836216afbc6c5400b2e ]
The Legion Go features detachable controllers which support a dual dinput mode. In this mode, the controllers appear under a single HID device with two applications.
Currently, both controllers appear under the same event device, causing their controls to be mixed up. This patch separates the two so that they can be used independently.
In addition, the latest firmware update for the Legion Go swaps the IDs to the ones used by the Legion Go 2, so add those IDs as well.
[jkosina@suse.com: improved shortlog] Signed-off-by: Antheas Kapenekakis lkml@antheas.dev Signed-off-by: Jiri Kosina jkosina@suse.com Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
Based on my analysis, here's my determination:
**Backport Status: YES**
This commit should be backported to stable kernel trees for the following reasons:
1. **Fixes a real user-facing bug**: The commit message clearly states "Currently, both controllers appear under the same event device, causing their controls to be mixed up." This is a functional bug where the Legion Go's detachable controllers cannot be used independently as intended - their inputs are incorrectly merged together.
2. **Hardware quirk fix**: This falls under the stable tree rules category of fixing "a hardware quirk." The Legion Go requires special handling for its dual dinput mode where two controllers appear as two applications under a single HID device.
3. **Small and contained change**: The patch only adds 4 lines total: - 2 new device ID definitions in `drivers/hid/hid-ids.h` - 2 corresponding quirk entries in `drivers/hid/hid-quirks.c`
4. **Low risk**: The change uses an existing, well-established quirk mechanism (`HID_QUIRK_MULTI_INPUT`) that's already used for dozens of similar gaming controllers (as seen in hid-quirks.c). This quirk simply ensures that when multiple HID reports come from different report IDs, they create separate input devices rather than merging into one.
5. **Device enablement**: The commit also adds support for new device IDs (0x61ed) used by newer firmware and Legion Go 2, which falls under the stable rule of "just add a device ID."
6. **User impact**: Without this fix, users cannot properly use the Legion Go's detachable controllers independently, which is a core feature of the device. The controllers' inputs being mixed together makes many games and applications unusable.
The `HID_QUIRK_MULTI_INPUT` flag modifies the behavior in `drivers/hid/hid-input.c:2305-2320` to ensure that different HID reports with different IDs create separate hidinput structures, resulting in separate `/dev/input/eventX` devices for each controller rather than a single merged device.
drivers/hid/hid-ids.h | 2 ++ drivers/hid/hid-quirks.c | 2 ++ 2 files changed, 4 insertions(+)
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h index 33cc5820f2be1..a687fbbb77b00 100644 --- a/drivers/hid/hid-ids.h +++ b/drivers/hid/hid-ids.h @@ -831,6 +831,8 @@ #define USB_DEVICE_ID_LENOVO_PIXART_USB_MOUSE_6019 0x6019 #define USB_DEVICE_ID_LENOVO_PIXART_USB_MOUSE_602E 0x602e #define USB_DEVICE_ID_LENOVO_PIXART_USB_MOUSE_6093 0x6093 +#define USB_DEVICE_ID_LENOVO_LEGION_GO_DUAL_DINPUT 0x6184 +#define USB_DEVICE_ID_LENOVO_LEGION_GO2_DUAL_DINPUT 0x61ed
#define USB_VENDOR_ID_LETSKETCH 0x6161 #define USB_DEVICE_ID_WP9620N 0x4d15 diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c index 9bf9ce8dc8032..90be93bdb0895 100644 --- a/drivers/hid/hid-quirks.c +++ b/drivers/hid/hid-quirks.c @@ -124,6 +124,8 @@ static const struct hid_device_id hid_quirks[] = { { HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_MOUSEPEN_I608X_V2), HID_QUIRK_MULTI_INPUT }, { HID_USB_DEVICE(USB_VENDOR_ID_KYE, USB_DEVICE_ID_KYE_PENSKETCH_T609A), HID_QUIRK_MULTI_INPUT }, { HID_USB_DEVICE(USB_VENDOR_ID_LABTEC, USB_DEVICE_ID_LABTEC_ODDOR_HANDBRAKE), HID_QUIRK_ALWAYS_POLL }, + { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_LEGION_GO_DUAL_DINPUT), HID_QUIRK_MULTI_INPUT }, + { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_LEGION_GO2_DUAL_DINPUT), HID_QUIRK_MULTI_INPUT }, { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_OPTICAL_USB_MOUSE_600E), HID_QUIRK_ALWAYS_POLL }, { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_PIXART_USB_MOUSE_608D), HID_QUIRK_ALWAYS_POLL }, { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_PIXART_USB_MOUSE_6019), HID_QUIRK_ALWAYS_POLL },