^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) .. SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) .. include:: <isonum.txt>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) Kernel driver dell-smm-hwmon
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) ============================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) :Copyright: |copy| 2002-2005 Massimo Dal Zotto <dz@debian.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) :Copyright: |copy| 2019 Giovanni Mascellani <gio@debian.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) -----------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) On many Dell laptops the System Management Mode (SMM) BIOS can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) queried for the status of fans and temperature sensors. Userspace
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) utilities like ``sensors`` can be used to return the readings. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) userspace suite `i8kutils`__ can also be used to read the sensors and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) automatically adjust fan speed (please notice that it currently uses
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) the deprecated ``/proc/i8k`` interface).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) __ https://github.com/vitorafsr/i8kutils
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) ``sysfs`` interface
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) -------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) Temperature sensors and fans can be queried and set via the standard
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) ``hwmon`` interface on ``sysfs``, under the directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) ``/sys/class/hwmon/hwmonX`` for some value of ``X`` (search for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) ``X`` such that ``/sys/class/hwmon/hwmonX/name`` has content
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) ``dell_smm``). A number of other attributes can be read or written:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) =============================== ======= =======================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) Name Perm Description
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) =============================== ======= =======================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) fan[1-3]_input RO Fan speed in RPM.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) fan[1-3]_label RO Fan label.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) pwm[1-3] RW Control the fan PWM duty-cycle.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) pwm1_enable WO Enable or disable automatic BIOS fan
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) control (not supported on all laptops,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) see below for details).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) temp[1-10]_input RO Temperature reading in milli-degrees
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) Celsius.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) temp[1-10]_label RO Temperature sensor label.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) =============================== ======= =======================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) Disabling automatic BIOS fan control
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) ------------------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) On some laptops the BIOS automatically sets fan speed every few
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) seconds. Therefore the fan speed set by mean of this driver is quickly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) overwritten.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) There is experimental support for disabling automatic BIOS fan
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) control, at least on laptops where the corresponding SMM command is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) known, by writing the value ``1`` in the attribute ``pwm1_enable``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) (writing ``2`` enables automatic BIOS control again). Even if you have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) more than one fan, all of them are set to either enabled or disabled
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) automatic fan control at the same time and, notwithstanding the name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) ``pwm1_enable`` sets automatic control for all fans.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) If ``pwm1_enable`` is not available, then it means that SMM codes for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) enabling and disabling automatic BIOS fan control are not whitelisted
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) for your hardware. It is possible that codes that work for other
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) laptops actually work for yours as well, or that you have to discover
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) new codes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) Check the list ``i8k_whitelist_fan_control`` in file
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) ``drivers/hwmon/dell-smm-hwmon.c`` in the kernel tree: as a first
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) attempt you can try to add your machine and use an already-known code
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) pair. If, after recompiling the kernel, you see that ``pwm1_enable``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) is present and works (i.e., you can manually control the fan speed),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) then please submit your finding as a kernel patch, so that other users
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) can benefit from it. Please see
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) :ref:`Documentation/process/submitting-patches.rst <submittingpatches>`
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) for information on submitting patches.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) If no known code works on your machine, you need to resort to do some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) probing, because unfortunately Dell does not publish datasheets for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) its SMM. You can experiment with the code in `this repository`__ to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) probe the BIOS on your machine and discover the appropriate codes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) __ https://github.com/clopez/dellfan/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) Again, when you find new codes, we'd be happy to have your patches!
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) Module parameters
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) -----------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) * force:bool
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) Force loading without checking for supported
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) models. (default: 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) * ignore_dmi:bool
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) Continue probing hardware even if DMI data does not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) match. (default: 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) * restricted:bool
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) Allow fan control only to processes with the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) ``CAP_SYS_ADMIN`` capability set or processes run
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) as root when using the legacy ``/proc/i8k``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) interface. In this case normal users will be able
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) to read temperature and fan status but not to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) control the fan. If your notebook is shared with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) other users and you don't trust them you may want
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) to use this option. (default: 1, only available
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) with ``CONFIG_I8K``)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) * power_status:bool
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) Report AC status in ``/proc/i8k``. (default: 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) only available with ``CONFIG_I8K``)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) * fan_mult:uint
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) Factor to multiply fan speed with. (default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) autodetect)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) * fan_max:uint
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) Maximum configurable fan speed. (default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) autodetect)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) Legacy ``/proc`` interface
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) --------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) .. warning:: This interface is obsolete and deprecated and should not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) used in new applications. This interface is only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) available when kernel is compiled with option
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) ``CONFIG_I8K``.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) The information provided by the kernel driver can be accessed by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) simply reading the ``/proc/i8k`` file. For example::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) $ cat /proc/i8k
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 1.0 A17 2J59L02 52 2 1 8040 6420 1 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) The fields read from ``/proc/i8k`` are::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 1.0 A17 2J59L02 52 2 1 8040 6420 1 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) | | | | | | | | | |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) | | | | | | | | | +------- 10. buttons status
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) | | | | | | | | +--------- 9. AC status
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) | | | | | | | +-------------- 8. fan0 RPM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) | | | | | | +------------------- 7. fan1 RPM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) | | | | | +--------------------- 6. fan0 status
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) | | | | +----------------------- 5. fan1 status
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) | | | +-------------------------- 4. temp0 reading (Celsius)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) | | +---------------------------------- 3. Dell service tag (later known as 'serial number')
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) | +-------------------------------------- 2. BIOS version
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) +------------------------------------------ 1. /proc/i8k format version
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) A negative value, for example -22, indicates that the BIOS doesn't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) return the corresponding information. This is normal on some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) models/BIOSes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) For performance reasons the ``/proc/i8k`` doesn't report by default
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) the AC status since this SMM call takes a long time to execute and is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) not really needed. If you want to see the ac status in ``/proc/i8k``
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) you must explictitly enable this option by passing the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) ``power_status=1`` parameter to insmod. If AC status is not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) available -1 is printed instead.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) The driver provides also an ioctl interface which can be used to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) obtain the same information and to control the fan status. The ioctl
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) interface can be accessed from C programs or from shell using the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) i8kctl utility. See the source file of ``i8kutils`` for more
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) information on how to use the ioctl interface.
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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