The following commit has been merged in the linux branch: commit ee1e82cee5e463a885d3c71acb2c769490e6927f Author: Dmitry Torokhov dmitry.torokhov@gmail.com Date: Mon Nov 2 21:57:40 2009 -0800

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

diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c index a315781..1df02d2 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");

/*