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hwmon: (dell-smm) Disallow fan_type() calls on broken machines

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Some Dell machines have especially broken SMM or BIOS which cause that once
fan_type() is called then CPU fan speed going randomly up and down. And for
fixing this behaviour reboot is required.

So this patch creates fan_type blacklist of affected Dell machines and
disallow fan_type() call on them to prevent that erratic behaviour.

Old blacklist which disabled loading driver on some machines added in
commits a4b45b25f1 ("hwmon: (dell-smm) Blacklist Dell Studio XPS 8100")
and 6220f4ebd7 ("hwmon: (dell-smm) Blacklist Dell Studio XPS 8000") were
moved to FAN_TYPE blacklist.

Reported-by: Jan C Peters <jcpeters89@gmail.com>
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=100121
Cc: stable@vger.kernel.org # v4.0+, will need backport
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Pali Rohár 2016-06-18 00:54:46 +02:00 committed by Guenter Roeck
parent 7613663cc1
commit 2744d2fde0
1 changed files with 25 additions and 11 deletions
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36
drivers/hwmon/dell-smm-hwmon.c
View file

@ -73,6 +73,7 @@ static u32 i8k_hwmon_flags;
static uint i8k_fan_mult = I8K_FAN_MULT;
static uint i8k_pwm_mult;
static uint i8k_fan_max = I8K_FAN_HIGH;
static bool disallow_fan_type_call;
#define I8K_HWMON_HAVE_TEMP1 (1 << 0)
#define I8K_HWMON_HAVE_TEMP2 (1 << 1)
@ -241,6 +242,9 @@ static int i8k_get_fan_type(int fan)
{
struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
if (disallow_fan_type_call)
return -EINVAL;
regs.ebx = fan & 0xff;
return i8k_smm(&regs) ? : regs.eax & 0xff;
}
@ -726,6 +730,9 @@ static struct attribute *i8k_attrs[] = {
static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
int index)
{
if (disallow_fan_type_call &&
(index == 9 || index == 12))
return 0;
if (index >= 0 && index <= 1 &&
!(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
return 0;
@ -937,12 +944,14 @@ static struct dmi_system_id i8k_dmi_table[] __initdata = {
MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
static struct dmi_system_id i8k_blacklist_dmi_table[] __initdata = {
/*
* On some machines once I8K_SMM_GET_FAN_TYPE is issued then CPU fan speed
* randomly going up and down due to bug in Dell SMM or BIOS. Here is blacklist
* of affected Dell machines for which we disallow I8K_SMM_GET_FAN_TYPE call.
* See bug: https://bugzilla.kernel.org/show_bug.cgi?id=100121
*/
static struct dmi_system_id i8k_blacklist_fan_type_dmi_table[] __initdata = {
{
/*
* CPU fan speed going up and down on Dell Studio XPS 8000
* for unknown reasons.
*/
.ident = "Dell Studio XPS 8000",
.matches = {
DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
@ -950,16 +959,19 @@ static struct dmi_system_id i8k_blacklist_dmi_table[] __initdata = {
},
},
{
/*
* CPU fan speed going up and down on Dell Studio XPS 8100
* for unknown reasons.
*/
.ident = "Dell Studio XPS 8100",
.matches = {
DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8100"),
},
},
{
.ident = "Dell Inspiron 580",
.matches = {
DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 580 "),
},
},
{ }
};
@ -974,8 +986,7 @@ static int __init i8k_probe(void)
/*
* Get DMI information
*/
if (!dmi_check_system(i8k_dmi_table) ||
dmi_check_system(i8k_blacklist_dmi_table)) {
if (!dmi_check_system(i8k_dmi_table)) {
if (!ignore_dmi && !force)
return -ENODEV;
@ -986,6 +997,9 @@ static int __init i8k_probe(void)
i8k_get_dmi_data(DMI_BIOS_VERSION));
}
if (dmi_check_system(i8k_blacklist_fan_type_dmi_table))
disallow_fan_type_call = true;
strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION),
sizeof(bios_version));
strlcpy(bios_machineid, i8k_get_dmi_data(DMI_PRODUCT_SERIAL),