[PATCH v2 1/2] i8042: Add forcenorestore quirk to leave controller untouched even on s3

[Werner Sembach <wse@tuxedocomputers.com>]

On s3 resume the i8042 driver tries to restore the controller to a known
state by reinitializing things, however can this confuses the controller
with different effects. Mostly occasionally unresponsive keyboards after
resume.

These issues do not rise on s0ix resume as here the controller is assumed
to preserved its state from before suspend.

This patch adds a quirk for devices where the reinitialization on s3 resume
is not needed and might be harmful as described above. It does this by
using the s0ix resume code path at selected locations.

This new quirk goes beyond what the preexisting reset=never quirk does,
which only skips some reinitialization steps.

Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
Cc: stable@vger.kernel.org
---
 drivers/input/serio/i8042-acpipnpio.h | 10 +++++++---
 drivers/input/serio/i8042.c           | 10 +++++++---
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/input/serio/i8042-acpipnpio.h b/drivers/input/serio/i8042-acpipnpio.h
index b585b1dab870e..10ec4534e5e14 100644
--- a/drivers/input/serio/i8042-acpipnpio.h
+++ b/drivers/input/serio/i8042-acpipnpio.h
@@ -83,6 +83,7 @@ static inline void i8042_write_command(int val)
 #define SERIO_QUIRK_KBDRESET		BIT(12)
 #define SERIO_QUIRK_DRITEK		BIT(13)
 #define SERIO_QUIRK_NOPNP		BIT(14)
+#define SERIO_QUIRK_FORCENORESTORE	BIT(15)
 
 /* Quirk table for different mainboards. Options similar or identical to i8042
  * module parameters.
@@ -1657,6 +1658,8 @@ static void __init i8042_check_quirks(void)
 	if (quirks & SERIO_QUIRK_NOPNP)
 		i8042_nopnp = true;
 #endif
+	if (quirks & SERIO_QUIRK_FORCENORESTORE)
+		i8042_forcenorestore = true;
 }
 #else
 static inline void i8042_check_quirks(void) {}
@@ -1690,7 +1693,7 @@ static int __init i8042_platform_init(void)
 
 	i8042_check_quirks();
 
-	pr_debug("Active quirks (empty means none):%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
+	pr_debug("Active quirks (empty means none):%s%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
 		i8042_nokbd ? " nokbd" : "",
 		i8042_noaux ? " noaux" : "",
 		i8042_nomux ? " nomux" : "",
@@ -1710,10 +1713,11 @@ static int __init i8042_platform_init(void)
 		"",
 #endif
 #ifdef CONFIG_PNP
-		i8042_nopnp ? " nopnp" : "");
+		i8042_nopnp ? " nopnp" : "",
 #else
-		"");
+		"",
 #endif
+		i8042_forcenorestore ? " forcenorestore" : "");
 
 	retval = i8042_pnp_init();
 	if (retval)
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 9fbb8d31575ae..2233d93f90e81 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -115,6 +115,10 @@ module_param_named(nopnp, i8042_nopnp, bool, 0);
 MODULE_PARM_DESC(nopnp, "Do not use PNP to detect controller settings");
 #endif
 
+static bool i8042_forcenorestore;
+module_param_named(forcenorestore, i8042_forcenorestore, bool, 0);
+MODULE_PARM_DESC(forcenorestore, "Force no restore on s3 resume, copying s2idle behaviour");
+
 #define DEBUG
 #ifdef DEBUG
 static bool i8042_debug;
@@ -1232,7 +1236,7 @@ static int i8042_pm_suspend(struct device *dev)
 {
 	int i;
 
-	if (pm_suspend_via_firmware())
+	if (!i8042_forcenorestore && pm_suspend_via_firmware())
 		i8042_controller_reset(true);
 
 	/* Set up serio interrupts for system wakeup. */
@@ -1248,7 +1252,7 @@ static int i8042_pm_suspend(struct device *dev)
 
 static int i8042_pm_resume_noirq(struct device *dev)
 {
-	if (!pm_resume_via_firmware())
+	if (i8042_forcenorestore || !pm_resume_via_firmware())
 		i8042_interrupt(0, NULL);
 
 	return 0;
@@ -1271,7 +1275,7 @@ static int i8042_pm_resume(struct device *dev)
 	 * not restore the controller state to whatever it had been at boot
 	 * time, so we do not need to do anything.
 	 */
-	if (!pm_suspend_via_firmware())
+	if (i8042_forcenorestore || !pm_suspend_via_firmware())
 		return 0;
 
 	/*
-- 
2.34.1