From: José Expósito <jose.exposito89@xxxxxxxxx> [ Upstream commit 37ef4c19b4c659926ce65a7ac709ceaefb211c40 ] Buttonpads are expected to map the INPUT_PROP_BUTTONPAD property bit and the BTN_LEFT key bit. As explained in the specification, where a device has a button type value of 0 (click-pad) or 1 (pressure-pad) there should not be discrete buttons: https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/touchpad-windows-precision-touchpad-collection#device-capabilities-feature-report However, some drivers map the BTN_RIGHT and/or BTN_MIDDLE key bits even though the device is a buttonpad and therefore does not have those buttons. This behavior has forced userspace applications like libinput to implement different workarounds and quirks to detect buttonpads and offer to the user the right set of features and configuration options. For more information: https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/726 In order to avoid this issue clear the BTN_RIGHT and BTN_MIDDLE key bits when the input device is register if the INPUT_PROP_BUTTONPAD property bit is set. Notice that this change will not affect udev because it does not check for buttons. See systemd/src/udev/udev-builtin-input_id.c. List of known affected hardware: - Chuwi AeroBook Plus - Chuwi Gemibook - Framework Laptop - GPD Win Max - Huawei MateBook 2020 - Prestigio Smartbook 141 C2 - Purism Librem 14v1 - StarLite Mk II - AMI firmware - StarLite Mk II - Coreboot firmware - StarLite Mk III - AMI firmware - StarLite Mk III - Coreboot firmware - StarLabTop Mk IV - AMI firmware - StarLabTop Mk IV - Coreboot firmware - StarBook Mk V Acked-by: Peter Hutterer <peter.hutterer@xxxxxxxxx> Acked-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> Acked-by: Jiri Kosina <jkosina@xxxxxxx> Signed-off-by: José Expósito <jose.exposito89@xxxxxxxxx> Link: https://lore.kernel.org/r/20220208174806.17183-1-jose.exposito89@xxxxxxxxx Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/input/input.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/input/input.c b/drivers/input/input.c index 3cfd2c18eebd9..ff9dc37eff345 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -2179,6 +2179,12 @@ int input_register_device(struct input_dev *dev) /* KEY_RESERVED is not supposed to be transmitted to userspace. */ __clear_bit(KEY_RESERVED, dev->keybit); + /* Buttonpads should not map BTN_RIGHT and/or BTN_MIDDLE. */ + if (test_bit(INPUT_PROP_BUTTONPAD, dev->propbit)) { + __clear_bit(BTN_RIGHT, dev->keybit); + __clear_bit(BTN_MIDDLE, dev->keybit); + } + /* Make sure that bitmasks not mentioned in dev->evbit are clean. */ input_cleanse_bitmasks(dev); -- 2.34.1
