From: "Pali Rohár" <pali.rohar@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Giovanni Mascellani <gio@debian.org>,
Jean Delvare <jdelvare@suse.com>,
linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] hwmon: (dell-smm-hwmon) Disable BIOS fan control on SET_FAN
Date: Thu, 14 Nov 2019 22:51:54 +0100 [thread overview]
Message-ID: <20191114215154.hze2avicv7pwiksp@pali> (raw)
In-Reply-To: <20191114213901.GA28532@roeck-us.net>
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On Thursday 14 November 2019 13:39:01 Guenter Roeck wrote:
> I can see two possibilities: Either add a pwm1_enable attribute to
> be able to set manual/automatic fan control,
I already proposed such patch in past:
https://patchwork.kernel.org/patch/9130921/
> > @@ -43,6 +49,8 @@
> > #define I8K_SMM_GET_TEMP_TYPE 0x11a3
> > #define I8K_SMM_GET_DELL_SIG1 0xfea3
> > #define I8K_SMM_GET_DELL_SIG2 0xffa3
> > +#define I8K_SMM_DISABLE_BIOS 0x30a3
> > +#define I8K_SMM_ENABLE_BIOS 0x31a3
This is model or BIOS specific. For example on E6440 are used 0x34a3 /
0x35a3 SMM calls. Because of these platform specific problems we have
never incorporated this patch into mainline kernel.
Also note that userspace can issue those SMM commands on its own (via
sys_iopl or sys_ioperm), fully bypassing such "protection" proposed in
this new patch.
--
Pali Rohár
pali.rohar@gmail.com
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next prev parent reply other threads:[~2019-11-14 21:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-14 21:14 [PATCH] hwmon: (dell-smm-hwmon) Disable BIOS fan control on SET_FAN Giovanni Mascellani
2019-11-14 21:39 ` Guenter Roeck
2019-11-14 21:51 ` Pali Rohár [this message]
2019-11-15 9:51 ` Giovanni Mascellani
2019-11-15 11:29 ` Pali Rohár
2019-11-15 13:44 ` Giovanni Mascellani
2019-11-15 14:36 ` Pali Rohár
2019-11-15 14:46 ` Guenter Roeck
2019-11-15 19:10 ` Giovanni Mascellani
2019-11-15 7:12 ` kbuild test robot
2019-11-15 8:19 ` kbuild test robot
2019-11-16 15:03 ` Pali Rohár
2019-11-16 17:14 ` Giovanni Mascellani
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