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>

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
 

drivers/input/serio/i8042-io.h

@@ -81,7 +81,7 @@ static inline int i8042_platform_init(void)
 		return -EBUSY;
 #endif
 
-	i8042_reset = 1;
+	i8042_reset = I8042_RESET_ALWAYS;
 	return 0;
 }
 

drivers/input/serio/i8042-ip22io.h

@@ -61,7 +61,7 @@ static inline int i8042_platform_init(void)
 		return -EBUSY;
 #endif
 
-	i8042_reset = 1;
+	i8042_reset = I8042_RESET_ALWAYS;
 
 	return 0;
 }

drivers/input/serio/i8042-ppcio.h

@@ -44,7 +44,7 @@ static inline void i8042_write_command(int val)
 
 static inline int i8042_platform_init(void)
 {
-	i8042_reset = 1;
+	i8042_reset = I8042_RESET_ALWAYS;
 	return 0;
 }
 

drivers/input/serio/i8042-sparcio.h

@@ -130,7 +130,7 @@ static int __init i8042_platform_init(void)
 		}
 	}
 
-	i8042_reset = 1;
+	i8042_reset = I8042_RESET_ALWAYS;
 
 	return 0;
 }

drivers/input/serio/i8042-unicore32io.h

@@ -61,7 +61,7 @@ static inline int i8042_platform_init(void)
 	if (!request_mem_region(I8042_REGION_START, I8042_REGION_SIZE, "i8042"))
 		return -EBUSY;
 
-	i8042_reset = 1;
+	i8042_reset = I8042_RESET_ALWAYS;
 	return 0;
 }
 

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 */
@@ -1072,12 +1156,18 @@ static int __init i8042_platform_init(void)
 		return retval;
 
 #if defined(__ia64__)
-        i8042_reset = true;
+        i8042_reset = I8042_RESET_ALWAYS;
 #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_DEFAULT) {
+		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;

drivers/input/serio/i8042.c

@@ -48,9 +48,39 @@ 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_S2RAM,
+#define I8042_RESET_DEFAULT	I8042_RESET_ON_S2RAM
+};
+static enum i8042_controller_reset_mode i8042_reset = I8042_RESET_DEFAULT;
+static int i8042_set_reset(const char *val, const struct kernel_param *kp)
+{
+	enum i8042_controller_reset_mode *arg = kp->arg;
+	int error;
+	bool reset;
+
+	if (val) {
+		error = kstrtobool(val, &reset);
+		if (error)
+			return error;
+	} else {
+		reset = true;
+	}
+
+	*arg = reset ? I8042_RESET_ALWAYS : I8042_RESET_NEVER;
+	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, enum i8042_controller_reset_mode)
+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);
@@ -1019,7 +1049,7 @@ static int i8042_controller_init(void)
  * Reset the controller and reset CRT to the original value set by BIOS.
  */
 
-static void i8042_controller_reset(bool force_reset)
+static void i8042_controller_reset(bool s2r_wants_reset)
 {
 	i8042_flush();
 
@@ -1044,8 +1074,10 @@ static void i8042_controller_reset(bool force_reset)
  * Reset the controller if requested.
  */
 
-	if (i8042_reset || force_reset)
+	if (i8042_reset == I8042_RESET_ALWAYS ||
+	    (i8042_reset == I8042_RESET_ON_S2RAM && s2r_wants_reset)) {
 		i8042_controller_selftest();
+	}
 
 /*
  * Restore the original control register setting.
@@ -1110,7 +1142,7 @@ static void i8042_dritek_enable(void)
  * before suspending.
  */
 
-static int i8042_controller_resume(bool force_reset)
+static int i8042_controller_resume(bool s2r_wants_reset)
 {
 	int error;
 
@@ -1118,7 +1150,8 @@ static int i8042_controller_resume(bool force_reset)
 	if (error)
 		return error;
 
-	if (i8042_reset || force_reset) {
+	if (i8042_reset == I8042_RESET_ALWAYS ||
+	    (i8042_reset == I8042_RESET_ON_S2RAM && s2r_wants_reset)) {
 		error = i8042_controller_selftest();
 		if (error)
 			return error;
@@ -1195,7 +1228,7 @@ static int i8042_pm_resume_noirq(struct device *dev)
 
 static int i8042_pm_resume(struct device *dev)
 {
-	bool force_reset;
+	bool want_reset;
 	int i;
 
 	for (i = 0; i < I8042_NUM_PORTS; i++) {
@@ -1218,9 +1251,9 @@ static int i8042_pm_resume(struct device *dev)
 	 * off control to the platform firmware, otherwise we can simply restore
 	 * the mode.
 	 */
-	force_reset = pm_resume_via_firmware();
+	want_reset = pm_resume_via_firmware();
 
-	return i8042_controller_resume(force_reset);
+	return i8042_controller_resume(want_reset);
 }
 
 static int i8042_pm_thaw(struct device *dev)
@@ -1481,7 +1514,7 @@ 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;