From 2744d2fde00dc8bcc3679eb72c81a63058e90faa Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pali=20Roh=C3=A1r?= Date: Sat, 18 Jun 2016 00:54:46 +0200 Subject: [PATCH] hwmon: (dell-smm) Disallow fan_type() calls on broken machines MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 a4b45b25f18d ("hwmon: (dell-smm) Blacklist Dell Studio XPS 8100") and 6220f4ebd7b4 ("hwmon: (dell-smm) Blacklist Dell Studio XPS 8000") were moved to FAN_TYPE blacklist. Reported-by: Jan C Peters Signed-off-by: Pali Rohár 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 --- drivers/hwmon/dell-smm-hwmon.c | 36 +++++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 11 deletions(-) diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c index c8bd3fdd0710..4bbc58714868 100644 --- a/drivers/hwmon/dell-smm-hwmon.c +++ b/drivers/hwmon/dell-smm-hwmon.c @@ -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(®s) ? : 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),