[PATCH 1/2] HID: logitech-hidpp: fix hi-res scroll for Bolt-connected MX Master
From: Erik Håkansson <hidden>
Date: 2026-09-22 17:40:42
Also in:
lkml
Subsystem:
hid core layer, hid logitech drivers, hid++ logitech drivers, the rest · Maintainers:
Jiri Kosina, Benjamin Tissoires, Linus Torvalds
From: Rafael Passos <redacted>
The new added support for Logitech HID++ caused this mouse to
scroll too far for each tic when using the USB dongle (Bolt).
Previously, this mouse was handled as hid_generic over the Bold
connection, and logitech-hidpp when over Bluetooth.
Cause:
Over the Bolt receiver, the mouse reports are forwarded over the generic
interface 1, instead of the new HID++ child device. The generic hid does
now know about the hi-res scrolling used by the HID++.
In my tests, I discovered this mouse has a multiplier factor of 15. This
multiplier is only handled by the logitech-hidpp driver. When piped to
hid_generic, the "hi-res" value was piped to a "low-res" field, making
the scroll unbearable.
The fix routes the wheel using the HID++, so the ticks are scaled by the
multiplier and correctly reported as a hi-res event.
I also had to move the hidpp_is_bolt_child function up, to use it in the
hidpp_connect_event function, where the gate for
hidpp_initialize_hires_scroll function lives.
Tested with:
- Logitech MX Master 3S (mouse) via Bolt receiver and Bluetooth.
Fixes: 022eb347ff3a ("HID: logitech: add Bolt receiver support for Logitech HID++ devices")
Signed-off-by: Rafael Passos <redacted>
Tested-by: Oleksandr Natalenko <redacted>
Tested-by: Alexey Zagorodnikov <redacted>
---
drivers/hid/hid-logitech-hidpp.c | 47 +++++++++++++++++++++++++++-------------
1 file changed, 32 insertions(+), 15 deletions(-)
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 4e00ac91493f..166980be57b7 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c@@ -3891,6 +3891,19 @@ static int hidpp10_consumer_keys_raw_event(struct hidpp_device *hidpp, return 1; } +static bool hidpp_is_bolt_child(struct hid_device *hdev) +{ + struct device *parent = hdev->dev.parent; + struct hid_device *receiver_hdev; + + if (!parent) + return false; + + receiver_hdev = to_hid_device(parent); + return receiver_hdev->vendor == USB_VENDOR_ID_LOGITECH && + receiver_hdev->product == USB_DEVICE_ID_LOGITECH_BOLT_RECEIVER; +} + /* -------------------------------------------------------------------------- */ /* High-resolution scroll wheels */ /* -------------------------------------------------------------------------- */
@@ -3901,7 +3914,9 @@ static int hi_res_scroll_enable(struct hidpp_device *hidpp) u8 multiplier = 1; if (hidpp->capabilities & HIDPP_CAPABILITY_HIDPP20_HI_RES_WHEEL) { - ret = hidpp_hrw_set_wheel_mode(hidpp, false, true, false); + bool use_hidpp = hidpp_is_bolt_child(hidpp->hid_dev); + + ret = hidpp_hrw_set_wheel_mode(hidpp, false, true, use_hidpp); if (ret == 0) ret = hidpp_hrw_get_wheel_capability(hidpp, &multiplier); } else if (hidpp->capabilities & HIDPP_CAPABILITY_HIDPP20_HI_RES_SCROLL) {
@@ -3989,6 +4004,19 @@ static int hidpp20_hires_wheel_raw_event(struct hidpp_device *hidpp, return 1; } + /* wheel movement event: 16-bit signed delta in HID++ ticks */ + if ((data[3] & 0xf0) == 0x00 && size >= 7 && hidpp->input && + hidpp->vertical_wheel_counter.wheel_multiplier) { + s16 delta = get_unaligned_be16(&data[5]); + + if (delta) { + hidpp_scroll_counter_handle_scroll(hidpp->input, + &hidpp->vertical_wheel_counter, delta); + input_sync(hidpp->input); + } + return 1; + } + return 0; }
@@ -4379,19 +4407,6 @@ static int hidpp_initialize_battery(struct hidpp_device *hidpp) return ret; } -static bool hidpp_is_bolt_child(struct hid_device *hdev) -{ - struct device *parent = hdev->dev.parent; - struct hid_device *receiver_hdev; - - if (!parent) - return false; - - receiver_hdev = to_hid_device(parent); - return receiver_hdev->vendor == USB_VENDOR_ID_LOGITECH && - receiver_hdev->product == USB_DEVICE_ID_LOGITECH_BOLT_RECEIVER; -} - static int hidpp_bolt_init(struct hidpp_device *hidpp) { struct hid_device *hdev = hidpp->hid_dev;
@@ -4553,7 +4568,9 @@ static void hidpp_connect_event(struct work_struct *work) } hidpp_initialize_battery(hidpp); - if (!hid_is_usb(hidpp->hid_dev)) + + if (!hid_is_usb(hidpp->hid_dev) || + hidpp_is_bolt_child(hidpp->hid_dev)) hidpp_initialize_hires_scroll(hidpp); /* forward current battery state */
--
2.55.0