From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755681AbYIQWXU (ORCPT ); Wed, 17 Sep 2008 18:23:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752987AbYIQWXM (ORCPT ); Wed, 17 Sep 2008 18:23:12 -0400 Received: from ch-smtp02.sth.basefarm.net ([80.76.149.213]:55173 "EHLO ch-smtp02.sth.basefarm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752926AbYIQWXM (ORCPT ); Wed, 17 Sep 2008 18:23:12 -0400 Message-ID: <48D1834D.5090406@euromail.se> Date: Thu, 18 Sep 2008 00:23:09 +0200 From: Henrik Rydberg User-Agent: Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: Nicolas Boichat , lm-sensors@lm-sensors.org CC: linux-kernel@vger.kernel.org Subject: [PATCH 2/5] hwmon: applesmc: Fix the 'wait status failed: c != 8' problem Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Originating-IP: 83.248.33.63 X-Scan-Result: No virus found in message 1Kg5QU-0002CJ-7D. X-Scan-Signature: ch-smtp02.sth.basefarm.net 1Kg5QU-0002CJ-7D a068797a49b73d71d7bc241c7009e001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On many Macbooks since mid 2007, the Pro, C2D and Air models, applesmc fails to read some or all SMC ports. This problem has various effects, such as flooded logfiles, malfunctioning temperature sensors, accelerometers failing to initialize, and difficulties getting backlight functionality to work properly. The root of the problem seems to be the command protocol. The current code sends out a command byte, then repeatedly polls for an ack before continuing to send or recieve data. From experiments leading to this patch, it seems the command protocol never quite worked or changed so that one now sends a command byte, waits a little bit, polls for an ack, and if it fails, repeats the whole thing by sending the command byte again. This patch implements a send_command function according to the new interpretation of the protocol, and should work also for earlier models. Signed-off-by: Henrik Rydberg --- drivers/hwmon/applesmc.c | 36 ++++++++++++++++++++++++++---------- 1 files changed, 26 insertions(+), 10 deletions(-) diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c index b401975..9a43c4b 100644 --- a/drivers/hwmon/applesmc.c +++ b/drivers/hwmon/applesmc.c @@ -191,6 +191,26 @@ static int __wait_status(u8 val) } /* + * special treatment of command port - on newer macbooks, it seems necessary + * to resend the command byte before polling the status again. Callers must + * hold applesmc_lock. + */ +static int send_command(u8 cmd) +{ + int i; + for (i = 0; i < 1000; i++) { + outb(cmd, APPLESMC_CMD_PORT); + udelay(5); + if ((inb(APPLESMC_CMD_PORT) & APPLESMC_STATUS_MASK) == 0x0c) + return 0; + udelay(5); + } + printk(KERN_WARNING "applesmc: command failed: %x -> %x\n", + cmd, inb(APPLESMC_CMD_PORT)); + return -EIO; +} + +/* * applesmc_read_key - reads len bytes from a given key, and put them in buffer. * Returns zero on success or a negative error on failure. Callers must * hold applesmc_lock. @@ -205,8 +225,7 @@ static int applesmc_read_key(const char* key, u8* buffer, u8 len) return -EINVAL; } - outb(APPLESMC_READ_CMD, APPLESMC_CMD_PORT); - if (__wait_status(0x0c)) + if (send_command(APPLESMC_READ_CMD)) return -EIO; for (i = 0; i < 4; i++) { @@ -249,8 +268,7 @@ static int applesmc_write_key(const char* key, u8* buffer, u8 len) return -EINVAL; } - outb(APPLESMC_WRITE_CMD, APPLESMC_CMD_PORT); - if (__wait_status(0x0c)) + if (send_command(APPLESMC_WRITE_CMD)) return -EIO; for (i = 0; i < 4; i++) { @@ -284,8 +302,7 @@ static int applesmc_get_key_at_index(int index, char* key) readkey[2] = index >> 8; readkey[3] = index; - outb(APPLESMC_GET_KEY_BY_INDEX_CMD, APPLESMC_CMD_PORT); - if (__wait_status(0x0c)) + if (send_command(APPLESMC_GET_KEY_BY_INDEX_CMD)) return -EIO; for (i = 0; i < 4; i++) { @@ -315,8 +332,7 @@ static int applesmc_get_key_type(char* key, char* type) { int i; - outb(APPLESMC_GET_KEY_TYPE_CMD, APPLESMC_CMD_PORT); - if (__wait_status(0x0c)) + if (send_command(APPLESMC_GET_KEY_TYPE_CMD)) return -EIO; for (i = 0; i < 4; i++) { -- 1.5.4.3