Input: i8042 - skip selftest on ASUS laptops

On suspend/resume cycle, selftest is executed to reset i8042 controller.
But when this is done in Asus devices, subsequent calls to detect/init
functions to elantech driver fails. Skipping selftest fixes this problem.

An easier step to reproduce this problem is adding i8042.reset=1 as a
kernel parameter. On Asus laptops, it'll make the system to start with the
touchpad already stuck, since psmouse_probe forcibly calls the selftest
function.

This patch was inspired by John Hiesey's change[1], but, since this problem
affects a lot of models of Asus, let's avoid running selftests on them.

All models affected by this problem:
A455LD
K401LB
K501LB
K501LX
R409L
V502LX
X302LA
X450LCP
X450LD
X455LAB
X455LDB
X455LF
Z450LA

[1]: https://marc.info/?l=linux-input&m=144312209020616&w=2

Fixes: "ETPS/2 Elantech Touchpad dies after resume from suspend"
(https://bugzilla.kernel.org/show_bug.cgi?id=107971)

Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 0b3de80ec8f6..3475b3297064 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1409,7 +1409,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
         i8042.nopnp     [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
                              controllers
         i8042.notimeout [HW] Ignore timeout condition signalled by controller
-        i8042.reset     [HW] Reset the controller during init and cleanup
+        i8042.reset     [HW] Reset the controller during init, cleanup and
+                             suspend-to-ram transitions, only during s2r
+                             transitions, or never reset
+                        Format: { 1 | Y | y | 0 | N | n }
+                        1, Y, y: always reset controller
+                        0, N, n: don't ever reset controller
+                        Default: only on s2r transitions on x86; most other
+                        architectures force reset to be always executed
         i8042.unlock    [HW] Unlock (ignore) the keylock
         i8042.kbdreset  [HW] Reset device connected to KBD port