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From: Stefan Kriwanek <dev@stefankriwanek.de>
To: Jiri Kosina <jkosina@suse.cz>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>, linux-input@vger.kernel.org
Subject: Re: [PATCH] hid: Fix Speedlink VAD Cezanne support for some devices
Date: Sun, 25 Aug 2013 10:46:13 +0200	[thread overview]
Message-ID: <5219C455.7040309@stefankriwanek.de> (raw)
In-Reply-To: <alpine.LNX.2.00.1307302258080.18809@pobox.suse.cz>

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@stefankriwanek.de>

---

--- 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@stefankriwanek.de>
+ *  Copyright (c) 2011, 2013 Stefan Kriwanek <dev@stefankriwanek.de>
  */
 
 /*
@@ -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)


  reply	other threads:[~2013-08-25  8:46 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-30 10:38 [PATCH] hid: Fix Speedlink VAD Cezanne support for some devices Stefan Kriwanek
2013-07-30 20:59 ` Jiri Kosina
2013-08-25  8:46   ` Stefan Kriwanek [this message]
2013-08-26 11:51     ` Jiri Kosina

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