linux-kernel - [patch 1/2] input: introduce a tougher i8042.reset

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Date:	Wed, 4 Feb 2009 19:16:31 -0800
From:	Arjan van de Ven <arjan@...radead.org>
To:	linux-input@...r.kernel.org
Cc:	Arjan van de Ven <arjan@...radead.org>,
	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Subject: [patch 1/2] input: introduce a tougher i8042.reset


>From 2c5ccde448ae5f4062802bcd6002f856acbd268f Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@...ux.intel.com>
Date: Tue, 3 Feb 2009 16:26:16 -0800
Subject: [PATCH] input: introduce a tougher i8042.reset

Some touchpads don't reset right the first time (MSI Wind U-100 for
example). This patch will retry the reset up to 5 times.

In addition, this patch also adds a module parameter to not treat
reset failures as fatal to the usage of the device. This prevents
a touchpad failure from also disabling the keyboard....

Signed-off-by: Arjan van de Ven <arjan@...ux.intel.com>
---
 Documentation/kernel-parameters.txt |    2 ++
 drivers/input/serio/i8042.c         |   33 ++++++++++++++++++++++++---------
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ac613a6..a43e3bd 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -855,6 +855,8 @@ and is between 256 and 4096 characters. It is defined in the file
 			[HW] Frequency with which keyboard LEDs should blink
 			     when kernel panics (default is 0.5 sec)
 	i8042.reset	[HW] Reset the controller during init and cleanup
+	i8042.nonfatal  [HW] Don't treat i8042.reset failures as fatal for the
+			     device initialization.
 	i8042.unlock	[HW] Unlock (ignore) the keylock
 
 	i810=		[HW,DRM]
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index 170f71e..2473a9a 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -47,6 +47,10 @@ static unsigned int i8042_reset;
 module_param_named(reset, i8042_reset, bool, 0);
 MODULE_PARM_DESC(reset, "Reset controller during init and cleanup.");
 
+static unsigned int i8042_nonfatal;
+module_param_named(nonfatal, i8042_nonfatal, bool, 0);
+MODULE_PARM_DESC(reset, "Treat controller test failures as non-fatal.");
+
 static unsigned int i8042_direct;
 module_param_named(direct, i8042_direct, bool, 0);
 MODULE_PARM_DESC(direct, "Put keyboard port into non-translated mode.");
@@ -712,22 +716,33 @@ static int i8042_controller_check(void)
 static int i8042_controller_selftest(void)
 {
 	unsigned char param;
+	int i = 0;
 
 	if (!i8042_reset)
 		return 0;
 
-	if (i8042_command(&param, I8042_CMD_CTL_TEST)) {
-		printk(KERN_ERR "i8042.c: i8042 controller self test timeout.\n");
-		return -ENODEV;
-	}
+	/*
+	 * We try this 5 times; on some really fragile systems this does not
+	 * take the first time...
+	 */
+	do {
+
+		if (i8042_command(&param, I8042_CMD_CTL_TEST)) {
+			printk(KERN_ERR "i8042.c: i8042 controller self test timeout.\n");
+			return -ENODEV;
+		}
+
+		if (param == I8042_RET_CTL_TEST)
+			return 0;
 
-	if (param != I8042_RET_CTL_TEST) {
 		printk(KERN_ERR "i8042.c: i8042 controller selftest failed. (%#x != %#x)\n",
-			 param, I8042_RET_CTL_TEST);
-		return -EIO;
-	}
+			param, I8042_RET_CTL_TEST);
+		msleep(50);
+	} while (i++ < 5);
 
-	return 0;
+	if (i8042_nonfatal)
+		return 0;
+	return -EIO;
 }
 
 /*
-- 
1.6.0.6



-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
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