redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

i8k: Rework error retries 

Instead of returning a previous value if the SMM code returns
an error when trying to read a temperature, retry once.
If that fails again, return -ENODATA. Also return -ENODATA if an
attempt is made to read the GPU temperature but the GPU is
currently turned off.

Drop the I8K_TEMPERATURE_BUG definition and handle the related bug
unconditionally.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Guenter Roeck 2015-01-12 14:32:00 +01:00 committed by Greg Kroah-Hartman
parent 83d514d762
commit 564132d9d6
1 changed files with 25 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
drivers/char/i8k.c
View File

@ -5,7 +5,7 @@
*
* Hwmon integration:
* Copyright (C) 2011 Jean Delvare <jdelvare@suse.de>
* Copyright (C) 2013 Guenter Roeck <linux@roeck-us.net>
* Copyright (C) 2013, 2014 Guenter Roeck <linux@roeck-us.net>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
@ -20,6 +20,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
@ -59,8 +60,6 @@
#define I8K_POWER_AC 0x05
#define I8K_POWER_BATTERY 0x01
#define I8K_TEMPERATURE_BUG 1
static DEFINE_MUTEX(i8k_mutex);
static char bios_version[4];
static struct device *i8k_hwmon_dev;
@ -300,39 +299,41 @@ static int i8k_get_temp_type(int sensor)
/*
* Read the cpu temperature.
*/
static int _i8k_get_temp(int sensor)
{
struct smm_regs regs = {
.eax = I8K_SMM_GET_TEMP,
.ebx = sensor & 0xff,
};
return i8k_smm(&regs) ? : regs.eax & 0xff;
}
static int i8k_get_temp(int sensor)
{
struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP, };
int rc;
int temp;
int temp = _i8k_get_temp(sensor);
#ifdef I8K_TEMPERATURE_BUG
static int prev[4] = { I8K_MAX_TEMP+1, I8K_MAX_TEMP+1, I8K_MAX_TEMP+1, I8K_MAX_TEMP+1 };
#endif
regs.ebx = sensor & 0xff;
rc = i8k_smm(&regs);
if (rc < 0)
return rc;
temp = regs.eax & 0xff;
#ifdef I8K_TEMPERATURE_BUG
/*
* Sometimes the temperature sensor returns 0x99, which is out of range.
* In this case we return (once) the previous cached value. For example:
* In this case we retry (once) before returning an error.
# 1003655137 00000058 00005a4b
# 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
# 1003655139 00000054 00005c52
*/
if (temp > I8K_MAX_TEMP) {
temp = prev[sensor];
prev[sensor] = I8K_MAX_TEMP+1;
} else {
prev[sensor] = temp;
if (temp == 0x99) {
msleep(100);
temp = _i8k_get_temp(sensor);
}
/*
* Return -ENODATA for all invalid temperatures.
*
* Known instances are the 0x99 value as seen above as well as
* 0xc1 (193), which may be returned when trying to read the GPU
* temperature if the system supports a GPU and it is currently
* turned off.
*/
if (temp > I8K_MAX_TEMP)
return -ENODATA;
#endif
return temp;
}