diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2015-01-12 14:32:00 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-01-25 09:17:58 -0800 |
| commit | 564132d9d62b3151dc6573da794378b5bf0cea17 (patch) | |
| tree | bfecf5fc4a7f7a9ec0b698e2d8f54976d2fe5245 /drivers/char | |
| parent | 83d514d76278e85cc74c472dd51687c8eb4faff0 (diff) | |
| download | lwn-564132d9d62b3151dc6573da794378b5bf0cea17.tar.gz lwn-564132d9d62b3151dc6573da794378b5bf0cea17.zip | |
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>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/i8k.c | 47 |
1 files changed, 24 insertions, 23 deletions
diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c index 1854faba8ae6..0e332fcd8fc3 100644 --- a/drivers/char/i8k.c +++ b/drivers/char/i8k.c @@ -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) +static int _i8k_get_temp(int sensor) { - struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP, }; - int rc; - int temp; + struct smm_regs regs = { + .eax = I8K_SMM_GET_TEMP, + .ebx = sensor & 0xff, + }; -#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(®s); - if (rc < 0) - return rc; + return i8k_smm(®s) ? : regs.eax & 0xff; +} - temp = regs.eax & 0xff; +static int i8k_get_temp(int sensor) +{ + int temp = _i8k_get_temp(sensor); -#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; } |