HID: logitech: Handle 0 scroll events for the m560

hidpp_scroll_counter_handle_scroll() doesn't expect a 0-value scroll event, it
gets interpreted as a negative scroll direction event. This can cause scroll
direction resets and thus broken scrolling.

Fixes: 4435ff2f09a2fc ("HID: logitech: Enable high-resolution scrolling on Logitech mice")
Cc: stable@vger.kernel.org # v5.0
Reported-and-tested-by: Aimo Metsälä <aimetsal@outlook.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 0a24324..199cc25 100644 (file)
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -2614,8 +2614,9 @@ static int m560_raw_event(struct hid_device *hdev, u8 *data, int size)
                input_report_rel(mydata->input, REL_Y, v);
 
                v = hid_snto32(data[6], 8);
-               hidpp_scroll_counter_handle_scroll(
-                               &hidpp->vertical_wheel_counter, v);
+               if (v != 0)
+                       hidpp_scroll_counter_handle_scroll(
+                                       &hidpp->vertical_wheel_counter, v);
 
                input_sync(mydata->input);
        }