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.) Hence, I believe it is safe to also apply to older kernels (that is, if your policy allows).
The patch applies to any kernel from 3.1 to current 3.11-rc6.
Signed-off-by: Stefan Kriwanek <mail@xxxxxxxxxxxxxxxxx>
---
--- linux-source-3.5.0/drivers/hid/hid-speedlink.c
+++ linux-source-3.5.0-speedlink/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 <mail@xxxxxxxxxxxxxxxxx>
+ * Copyright (c) 2011, 2013 Stefan Kriwanek <dev@xxxxxxxxxxxxxxxxx>
*/
/*
@@ -48,8 +48,13 @@ static int speedlink_event(struct hid_de
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)
--
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