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hwmon: (dell-smm) Disallow fan_type() calls on broken machines
authorPali Rohár <pali.rohar@gmail.com>
Fri, 17 Jun 2016 22:54:46 +0000 (00:54 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 27 Jul 2016 16:47:37 +0000 (09:47 -0700)
commit9a3d983a442aaaaa1b2c64f1c6b4b9d086db5a78
treed65f7aeca568c17a7c197c66319dd1dd0eadb3c7
parent5c4182130d09db73fab11a23184b1215806877e1
hwmon: (dell-smm) Disallow fan_type() calls on broken machines

commit 2744d2fde00dc8bcc3679eb72c81a63058e90faa upstream.

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 <jcpeters89@gmail.com>
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=100121
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/hwmon/dell-smm-hwmon.c