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authorPhoenix Huang <phoenix@emc.com.tw>2021-11-07 22:00:03 -0800
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2021-11-09 22:22:43 -0800
commitbe896bd3b72b44126c55768f14c22a8729b0992e (patch)
treea49f6768224c13a53fd3834207843a7da702d2fd /drivers/input
parent6e4860410b828f8576c0c003d412fcf8a7d433f9 (diff)
downloadlinux-next-be896bd3b72b44126c55768f14c22a8729b0992e.tar.gz
Input: elantench - fix misreporting trackpoint coordinates
Some firmwares occasionally report bogus data from trackpoint, with X or Y displacement being too large (outside of [-127, 127] range). Let's drop such packets so that we do not generate jumps. Signed-off-by: Phoenix Huang <phoenix@emc.com.tw> Tested-by: Yufei Du <yufeidu@cs.unc.edu> Link: https://lore.kernel.org/r/20210729010940.5752-1-phoenix@emc.com.tw Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'drivers/input')
-rw-r--r--drivers/input/mouse/elantech.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index 2d0bc029619f..956d9cd34796 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -517,6 +517,19 @@ static void elantech_report_trackpoint(struct psmouse *psmouse,
case 0x16008020U:
case 0x26800010U:
case 0x36808000U:
+
+ /*
+ * This firmware misreport coordinates for trackpoint
+ * occasionally. Discard packets outside of [-127, 127] range
+ * to prevent cursor jumps.
+ */
+ if (packet[4] == 0x80 || packet[5] == 0x80 ||
+ packet[1] >> 7 == packet[4] >> 7 ||
+ packet[2] >> 7 == packet[5] >> 7) {
+ elantech_debug("discarding packet [%6ph]\n", packet);
+ break;
+
+ }
x = packet[4] - (int)((packet[1]^0x80) << 1);
y = (int)((packet[2]^0x80) << 1) - packet[5];