[PATCH] input/serio/i8042.c: Skipt selftest on ASUS laptops

[Marcos Paulo de Souza <marcos.souza.org@gmail.com>]

On suspend/resume cycle, selftest is executed to reset i8042 controller.
But when this is done in Asus devices, posterior 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>
---
 drivers/input/serio/i8042-x86ia64io.h | 94 ++++++++++++++++++++++++++++++++++-
 drivers/input/serio/i8042.c           | 39 ++++++++++++---
 2 files changed, 125 insertions(+), 8 deletions(-)

diff --git a/drivers/input/serio/i8042-x86ia64io.h b/drivers/input/serio/i8042-x86ia64io.h
index 68f5f4a..0d96539 100644
--- a/drivers/input/serio/i8042-x86ia64io.h
+++ b/drivers/input/serio/i8042-x86ia64io.h
@@ -510,6 +510,90 @@ static const struct dmi_system_id __initconst i8042_dmi_nomux_table[] = {
 	{ }
 };
 
+/*
+ * On some Asus laptops, just running self tests cause problems.
+ */
+static const struct dmi_system_id i8042_dmi_noselftest_table[] = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "A455LD"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "K401LB"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "K501LB"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "K501LX"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "R409L"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "V502LX"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "X302LA"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "X450LCP"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "X450LD"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "X455LAB"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "X455LDB"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "X455LF"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Z450LA"),
+		},
+	},
+	{ }
+};
 static const struct dmi_system_id __initconst i8042_dmi_reset_table[] = {
 	{
 		/* MSI Wind U-100 */
@@ -1076,8 +1160,14 @@ static int __init i8042_platform_init(void)
 #endif
 
 #ifdef CONFIG_X86
-	if (dmi_check_system(i8042_dmi_reset_table))
-		i8042_reset = true;
+	/* Honor module parameter when value is not default */
+	if (i8042_reset == I8042_RESET_ON_RESUME) {
+		if (dmi_check_system(i8042_dmi_reset_table))
+			i8042_reset = I8042_RESET_ALWAYS;
+
+		if (dmi_check_system(i8042_dmi_noselftest_table))
+			i8042_reset = I8042_RESET_NEVER;
+	}
 
 	if (dmi_check_system(i8042_dmi_noloop_table))
 		i8042_noloop = true;
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 405252a..c0e76c2 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -48,9 +48,33 @@ static bool i8042_unlock;
 module_param_named(unlock, i8042_unlock, bool, 0);
 MODULE_PARM_DESC(unlock, "Ignore keyboard lock.");
 
-static bool i8042_reset;
-module_param_named(reset, i8042_reset, bool, 0);
-MODULE_PARM_DESC(reset, "Reset controller during init and cleanup.");
+enum i8042_controller_reset_mode {
+	I8042_RESET_NEVER,
+	I8042_RESET_ALWAYS,
+	I8042_RESET_ON_RESUME
+};
+static unsigned int i8042_reset = I8042_RESET_ON_RESUME;
+static int i8042_set_reset(const char *val, const struct kernel_param *kp)
+{
+	unsigned int ret = I8042_RESET_ON_RESUME;
+
+	if (!val || !strncmp(val, "1", 1) || !strncasecmp(val, "y", 1))
+		ret = I8042_RESET_ALWAYS;
+	else if (!strncmp(val, "0", 1) || !strncasecmp(val, "n", 1))
+		ret = I8042_RESET_NEVER;
+
+	*((unsigned int *)kp->arg) = ret;
+
+	return 0;
+}
+
+static const struct kernel_param_ops param_ops_reset_param = {
+	.flags = KERNEL_PARAM_OPS_FL_NOARG,
+	.set = i8042_set_reset,
+};
+#define param_check_reset_param(name, p) __param_check(name, p, unsigned int)
+module_param_named(reset, i8042_reset, reset_param, 0);
+MODULE_PARM_DESC(reset, "Reset controller on resume, cleanup or both");
 
 static bool i8042_direct;
 module_param_named(direct, i8042_direct, bool, 0);
@@ -890,6 +914,9 @@ static int i8042_controller_selftest(void)
 	unsigned char param;
 	int i = 0;
 
+	if (i8042_reset == I8042_RESET_NEVER)
+		return 0;
+
 	/*
 	 * We try this 5 times; on some really fragile systems this does not
 	 * take the first time...
@@ -1044,7 +1071,7 @@ static void i8042_controller_reset(bool force_reset)
  * Reset the controller if requested.
  */
 
-	if (i8042_reset || force_reset)
+	if (i8042_reset != I8042_RESET_NEVER || force_reset)
 		i8042_controller_selftest();
 
 /*
@@ -1118,7 +1145,7 @@ static int i8042_controller_resume(bool force_reset)
 	if (error)
 		return error;
 
-	if (i8042_reset || force_reset) {
+	if (i8042_reset != I8042_RESET_NEVER || force_reset) {
 		error = i8042_controller_selftest();
 		if (error)
 			return error;
@@ -1482,7 +1509,7 @@ static int __init i8042_probe(struct platform_device *dev)
 
 	i8042_platform_device = dev;
 
-	if (i8042_reset) {
+	if (i8042_reset == I8042_RESET_ALWAYS) {
 		error = i8042_controller_selftest();
 		if (error)
 			return error;
-- 
2.7.4