[patch 16/54] Input: i8042 - fix AUX port detection with some chips

Chris Wright
2007-06-08T08:08:05Z

[-- Attachment #1: input-i8042-fix-aux-port-detection-with-some-chips.patch --]
[-- Type: text/plain, Size: 2623 bytes --]

-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Roland Scheidegger <sroland@tungstengraphics.com>

The i8042 driver fails detection of the AUX port with some chips,
because they apparently do not change the I8042_CTR_AUXDIS bit
immediately. This is known to affect at least HP500/HP510 notebooks,
consequently the built-in touchpad will not work. The patch will simply
reread the value until it gets the expected value or a retry limit is
hit, without touching other workaround code in the same area.

Signed-off-by: Roland Scheidegger <sroland@tungstengraphics.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=d2ada5597d33a9108acb2caf912f85cbc9caab1e

drivers/input/serio/i8042.c | 35 +++++++++++++++++++++++++++++------
1 file changed, 29 insertions(+), 6 deletions(-)

--- linux-2.6.21.4.orig/drivers/input/serio/i8042.c
+++ linux-2.6.21.4/drivers/input/serio/i8042.c
@@ -526,6 +526,33 @@ static irqreturn_t __devinit i8042_aux_t
return IRQ_HANDLED;
}

+/*
+ * i8042_toggle_aux - enables or disables AUX port on i8042 via command and
+ * verifies success by readinng CTR. Used when testing for presence of AUX
+ * port.
+ */
+static int __devinit i8042_toggle_aux(int on)
+{
+ unsigned char param;
+ int i;
+
+ if (i8042_command(&param,
+ on ? I8042_CMD_AUX_ENABLE : I8042_CMD_AUX_DISABLE))
+ return -1;
+
+ /* some chips need some time to set the I8042_CTR_AUXDIS bit */
+ for (i = 0; i < 100; i++) {
+ udelay(50);
+
+ if (i8042_command(&param, I8042_CMD_CTL_RCTR))
+ return -1;
+
+ if (!(param & I8042_CTR_AUXDIS) == on)
+ return 0;
+ }
+
+ return -1;
+}

/*
* i8042_check_aux() applies as much paranoia as it can at detecting
@@ -580,16 +607,12 @@ static int __devinit i8042_check_aux(voi
* Bit assignment test - filters out PS/2 i8042's in AT mode
*/

- if (i8042_command(&param, I8042_CMD_AUX_DISABLE))
- return -1;
- if (i8042_command(&param, I8042_CMD_CTL_RCTR) || (~param & I8042_CTR_AUXDIS)) {
+ if (i8042_toggle_aux(0)) {
printk(KERN_WARNING "Failed to disable AUX port, but continuing anyway... Is this a SiS?\n");
printk(KERN_WARNING "If AUX port is really absent please use the 'i8042.noaux' option.\n");
}

- if (i8042_command(&param, I8042_CMD_AUX_ENABLE))
- return -1;
- if (i8042_command(&param, I8042_CMD_CTL_RCTR) || (param & I8042_CTR_AUXDIS))
+ if (i8042_toggle_aux(1))
return -1;

/*

--