diff mbox series

HID: lenovo: Add middleclick_workaround sysfs knob for cptkbd

Message ID 20230918145042.37368-1-me@khvoinitsky.org (mailing list archive)
State New
Delegated to: Jiri Kosina
Headers show
Series HID: lenovo: Add middleclick_workaround sysfs knob for cptkbd | expand

Commit Message

Mikhail Khvainitski Sept. 18, 2023, 2:50 p.m. UTC 
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 makes it possible to disable this
workaround by sysfs knob.

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

Signed-off-by: Mikhail Khvainitski <me@khvoinitsky.org>
---
 drivers/hid/hid-lenovo.c | 84 +++++++++++++++++++++++++++++-----------
 1 file changed, 62 insertions(+), 22 deletions(-)

Comments

Mikhail Khvainitski Sept. 23, 2023, 10:58 p.m. UTC | #1 
So, while I was waiting for the review of the patch, I've come up with
much better idea: we can just autodetect if stock and buggy or
patched and bug-free firmware is used and have no need to introduce
additional sysfs knob. So the patch which implements this follows in
the next message.

While the patch is ready to be merged as is (of course, if there are
no comments from reviewers), I thought about the following: may be we
should add a message to dmesg upon detecting stock and buggy firmware
that user should consider patching the firmware? If so, what is the
best place to put an instruction to? Post a link to dmesg? Can the
link point directly to Dennis' blog or its better to put it somewhere
else (with credits, of course)?

Thanks.
diff mbox series

Patch

diff --git a/drivers/hid/hid-lenovo.c b/drivers/hid/hid-lenovo.c
index 44763c0da444..8993fa1ce66a 100644
--- a/drivers/hid/hid-lenovo.c
+++ b/drivers/hid/hid-lenovo.c
@@ -53,6 +53,7 @@  struct lenovo_drvdata {
 	int press_speed;
 	u8 middlebutton_state; /* 0:Up, 1:Down (undecided), 2:Scrolling */
 	bool fn_lock;
+	bool middleclick_workaround_cptkbd;
 };
 
 #define map_key_clear(c) hid_map_usage_clear(hi, usage, bit, max, EV_KEY, (c))
@@ -603,6 +604,36 @@  static ssize_t attr_sensitivity_store_cptkbd(struct device *dev,
 	return count;
 }
 
+static ssize_t attr_middleclick_workaround_show_cptkbd(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct lenovo_drvdata *cptkbd_data = hid_get_drvdata(hdev);
+
+	return snprintf(buf, PAGE_SIZE, "%u\n",
+		cptkbd_data->middleclick_workaround_cptkbd);
+}
+
+static ssize_t attr_middleclick_workaround_store_cptkbd(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct lenovo_drvdata *cptkbd_data = hid_get_drvdata(hdev);
+	int value;
+
+	if (kstrtoint(buf, 10, &value))
+		return -EINVAL;
+	if (value < 0 || value > 1)
+		return -EINVAL;
+
+	cptkbd_data->middleclick_workaround_cptkbd = !!value;
+
+	return count;
+}
+
 
 static struct device_attribute dev_attr_fn_lock =
 	__ATTR(fn_lock, S_IWUSR | S_IRUGO,
@@ -614,10 +645,16 @@  static struct device_attribute dev_attr_sensitivity_cptkbd =
 			attr_sensitivity_show_cptkbd,
 			attr_sensitivity_store_cptkbd);
 
+static struct device_attribute dev_attr_middleclick_workaround_cptkbd =
+	__ATTR(middleclick_workaround, S_IWUSR | S_IRUGO,
+			attr_middleclick_workaround_show_cptkbd,
+			attr_middleclick_workaround_store_cptkbd);
+
 
 static struct attribute *lenovo_attributes_cptkbd[] = {
 	&dev_attr_fn_lock.attr,
 	&dev_attr_sensitivity_cptkbd.attr,
+	&dev_attr_middleclick_workaround_cptkbd.attr,
 	NULL
 };
 
@@ -668,31 +705,33 @@  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->middleclick_workaround_cptkbd) {
+		/* "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);
+		/* 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) {
@@ -1146,6 +1185,7 @@  static int lenovo_probe_cptkbd(struct hid_device *hdev)
 	cptkbd_data->middlebutton_state = 0;
 	cptkbd_data->fn_lock = true;
 	cptkbd_data->sensitivity = 0x05;
+	cptkbd_data->middleclick_workaround_cptkbd = true;
 	lenovo_features_set_cptkbd(hdev);
 
 	ret = sysfs_create_group(&hdev->dev.kobj, &lenovo_attr_group_cptkbd);