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authorDmitry Torokhov <dmitry.torokhov@gmail.com>2009-11-02 21:57:40 -0800
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2009-11-02 22:11:43 -0800
commitee1e82cee5e463a885d3c71acb2c769490e6927f (patch)
tree288e9baeae958db78a170e18b8c885699cfbf198
parent7a53c7f56bbfc9b0ef892e68f5cfae3d902544d1 (diff)
Input: i8042 - try to get stable CTR value when initializing
If user presses keys while i8042 is being initialized there is a chance that keyboard data will be mistaken for results of Read Control Register command causing futher troubles. Work around this issue by reading CTR several times and stop when we get matching results. Reported-and-tested-by: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
-rw-r--r--drivers/input/serio/i8042.c35
1 files changed, 28 insertions, 7 deletions
diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
index a31578170ccc..1df02d25aca5 100644
--- a/drivers/input/serio/i8042.c
+++ b/drivers/input/serio/i8042.c
@@ -836,17 +836,32 @@ static int i8042_controller_selftest(void)
static int i8042_controller_init(void)
{
unsigned long flags;
+ int n = 0;
+ unsigned char ctr[2];
/*
- * Save the CTR for restoral on unload / reboot.
+ * Save the CTR for restore on unload / reboot.
*/
- if (i8042_command(&i8042_ctr, I8042_CMD_CTL_RCTR)) {
- printk(KERN_ERR "i8042.c: Can't read CTR while initializing i8042.\n");
- return -EIO;
- }
+ do {
+ if (n >= 10) {
+ printk(KERN_ERR
+ "i8042.c: Unable to get stable CTR read.\n");
+ return -EIO;
+ }
+
+ if (n != 0)
+ udelay(50);
+
+ if (i8042_command(&ctr[n++ % 2], I8042_CMD_CTL_RCTR)) {
+ printk(KERN_ERR
+ "i8042.c: Can't read CTR while initializing i8042.\n");
+ return -EIO;
+ }
- i8042_initial_ctr = i8042_ctr;
+ } while (n < 2 || ctr[0] != ctr[1]);
+
+ i8042_initial_ctr = i8042_ctr = ctr[0];
/*
* Disable the keyboard interface and interrupt.
@@ -895,6 +910,12 @@ static int i8042_controller_init(void)
return -EIO;
}
+/*
+ * Flush whatever accumulated while we were disabling keyboard port.
+ */
+
+ i8042_flush();
+
return 0;
}
@@ -914,7 +935,7 @@ static void i8042_controller_reset(void)
i8042_ctr |= I8042_CTR_KBDDIS | I8042_CTR_AUXDIS;
i8042_ctr &= ~(I8042_CTR_KBDINT | I8042_CTR_AUXINT);
- if (i8042_command(&i8042_initial_ctr, I8042_CMD_CTL_WCTR))
+ if (i8042_command(&i8042_ctr, I8042_CMD_CTL_WCTR))
printk(KERN_WARNING "i8042.c: Can't write CTR while resetting.\n");
/*