[PATCH AUTOSEL 6.5 14/34] HID: lenovo: Detect quirk-free fw on cptkbd and stop applying workaround

Sasha Levin
2023-11-07T15:52:47Z

From: Mikhail Khvainitski <me@khvoinitsky.org>

[ Upstream commit 46a0a2c96f0f47628190f122c2e3d879e590bcbe ]

Built-in firmware of cptkbd handles scrolling by itself (when middle
button is pressed) but with issues: it does not support horizontal and
hi-res scrolling and upon middle button release it sends middle button
click even if there was a scrolling event. Commit 3cb5ff0220e3 ("HID:
lenovo: Hide middle-button press until release") workarounds last
issue but it's impossible to workaround scrolling-related issues
without firmware modification.

Likely, Dennis Schneider has reverse engineered the firmware and
provided an instruction on how to patch it [1]. However,
aforementioned workaround prevents userspace (libinput) from knowing
exact moment when middle button has been pressed down and performing
"On-Button scrolling". This commit detects correctly-behaving patched
firmware if cursor movement events has been received during middle
button being pressed and stops applying workaround for this device.

Link: https://hohlerde.org/rauch/en/elektronik/projekte/tpkbd-fix/ [1]

Signed-off-by: Mikhail Khvainitski <me@khvoinitsky.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hid/hid-lenovo.c | 68 ++++++++++++++++++++++++++--------------
1 file changed, 45 insertions(+), 23 deletions(-)

diff --git a/drivers/hid/hid-lenovo.c b/drivers/hid/hid-lenovo.c
index 44763c0da4441..9c1181313e44d 100644
--- a/drivers/hid/hid-lenovo.c
+++ b/drivers/hid/hid-lenovo.c
@@ -51,7 +51,12 @@ struct lenovo_drvdata {
int select_right;
int sensitivity;
int press_speed;
- u8 middlebutton_state; /* 0:Up, 1:Down (undecided), 2:Scrolling */
+ /* 0: Up
+ * 1: Down (undecided)
+ * 2: Scrolling
+ * 3: Patched firmware, disable workaround
+ */
+ u8 middlebutton_state;
bool fn_lock;
};

@@ -668,31 +673,48 @@ static int lenovo_event_cptkbd(struct hid_device *hdev,
{
struct lenovo_drvdata *cptkbd_data = hid_get_drvdata(hdev);

- /* "wheel" scroll events */
- if (usage->type == EV_REL && (usage->code == REL_WHEEL ||
- usage->code == REL_HWHEEL)) {
- /* Scroll events disable middle-click event */
- cptkbd_data->middlebutton_state = 2;
- return 0;
- }
+ if (cptkbd_data->middlebutton_state != 3) {
+ /* REL_X and REL_Y events during middle button pressed
+ * are only possible on patched, bug-free firmware
+ * so set middlebutton_state to 3
+ * to never apply workaround anymore
+ */
+ if (cptkbd_data->middlebutton_state == 1 &&
+ usage->type == EV_REL &&
+ (usage->code == REL_X || usage->code == REL_Y)) {
+ cptkbd_data->middlebutton_state = 3;
+ /* send middle button press which was hold before */
+ input_event(field->hidinput->input,
+ EV_KEY, BTN_MIDDLE, 1);
+ input_sync(field->hidinput->input);
+ }

- /* Middle click events */
- if (usage->type == EV_KEY && usage->code == BTN_MIDDLE) {
- if (value == 1) {
- cptkbd_data->middlebutton_state = 1;
- } else if (value == 0) {
- if (cptkbd_data->middlebutton_state == 1) {
- /* No scrolling inbetween, send middle-click */
- input_event(field->hidinput->input,
- EV_KEY, BTN_MIDDLE, 1);
- input_sync(field->hidinput->input);
- input_event(field->hidinput->input,
- EV_KEY, BTN_MIDDLE, 0);
- input_sync(field->hidinput->input);
+ /* "wheel" scroll events */
+ if (usage->type == EV_REL && (usage->code == REL_WHEEL ||
+ usage->code == REL_HWHEEL)) {
+ /* Scroll events disable middle-click event */
+ cptkbd_data->middlebutton_state = 2;
+ return 0;
+ }
+
+ /* Middle click events */
+ if (usage->type == EV_KEY && usage->code == BTN_MIDDLE) {
+ if (value == 1) {
+ cptkbd_data->middlebutton_state = 1;
+ } else if (value == 0) {
+ if (cptkbd_data->middlebutton_state == 1) {
+ /* No scrolling inbetween, send middle-click */
+ input_event(field->hidinput->input,
+ EV_KEY, BTN_MIDDLE, 1);
+ input_sync(field->hidinput->input);
+ input_event(field->hidinput->input,
+ EV_KEY, BTN_MIDDLE, 0);
+ input_sync(field->hidinput->input);
+ }
+ cptkbd_data->middlebutton_state = 0;
}
- cptkbd_data->middlebutton_state = 0;
+ return 1;
}
- return 1;
}

if (usage->type == EV_KEY && usage->code == KEY_FN_ESC && value == 1) {
--
2.42.0