Commit 46a0a2c9 authored by Mikhail Khvainitski's avatar Mikhail Khvainitski Committed by Jiri Kosina
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HID: lenovo: Detect quirk-free fw on cptkbd and stop applying workaround 

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 3cb5ff02 ("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: default avatarMikhail Khvainitski <me@khvoinitsky.org>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 29aa98d0

drivers/hid/hid-lenovo.c

+45 −23
Original line number Diff line number Diff line
@@ -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;

};
@@ -668,6 +673,22 @@ static int lenovo_event_cptkbd(struct hid_device *hdev, 
{

	struct lenovo_drvdata *cptkbd_data = hid_get_drvdata(hdev);



	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);

		}



		/* "wheel" scroll events */

		if (usage->type == EV_REL && (usage->code == REL_WHEEL ||

				usage->code == REL_HWHEEL)) {
@@ -694,6 +715,7 @@ static int lenovo_event_cptkbd(struct hid_device *hdev, 
			}

			return 1;

		}

	}



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

		/*