From 06bb5219118fb098f4b0c7dcb484b28a52bf1c14 Mon Sep 17 00:00:00 2001 From: Stefan Kriwanek Date: Sun, 25 Aug 2013 10:46:13 +0200 Subject: [PATCH] HID: Fix Speedlink VAD Cezanne support for some devices Some devices of the "Speedlink VAD Cezanne" model need more aggressive fixing than already done. I made sure through testing that this patch would not interfere with the proper working of a device that is bug-free. (The driver drops EV_REL events with abs(val) >= 256, which are not achievable even on the highest laser resolution hardware setting.) Signed-off-by: Stefan Kriwanek Signed-off-by: Jiri Kosina --- drivers/hid/hid-speedlink.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/hid/hid-speedlink.c b/drivers/hid/hid-speedlink.c index a2f587d004e1..7112f3e832ee 100644 --- a/drivers/hid/hid-speedlink.c +++ b/drivers/hid/hid-speedlink.c @@ -3,7 +3,7 @@ * Fixes "jumpy" cursor and removes nonexistent keyboard LEDS from * the HID descriptor. * - * Copyright (c) 2011 Stefan Kriwanek + * Copyright (c) 2011, 2013 Stefan Kriwanek */ /* @@ -46,8 +46,13 @@ static int speedlink_event(struct hid_device *hdev, struct hid_field *field, struct hid_usage *usage, __s32 value) { /* No other conditions due to usage_table. */ - /* Fix "jumpy" cursor (invalid events sent by device). */ - if (value == 256) + + /* This fixes the "jumpy" cursor occuring due to invalid events sent + * by the device. Some devices only send them with value==+256, others + * don't. However, catching abs(value)>=256 is restrictive enough not + * to interfere with devices that were bug-free (has been tested). + */ + if (abs(value) >= 256) return 1; /* Drop useless distance 0 events (on button clicks etc.) as well */ if (value == 0)