mirror of
https://github.com/lm-sensors/lm-sensors.git
synced 2026-10-14 10:29:31 +00:00
Mark D. Studebaker
1bdaa54d40
patch from Philip Pokorny git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@1738 7894878c-1315-0410-8ee3-d5d059ff63e0
103 lines
2.8 KiB
Plaintext
103 lines
2.8 KiB
Plaintext
VID pin settings
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--------------------
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The VID (Voltage Identification) pins on sensor chips
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are used to read the CPU Core voltage setting.
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The VID setting can be controlled by jumpers on the board,
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or, in newer motherboards, by settings in the BIOS.
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On these newer boards, the BIOS programs some device's
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pins which in turn controls a DC-DC Converter to set its
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output to a certain voltage. These pins are also connected to
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the sensor chip so that the VID setting can be read back
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by applications.
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There are generally 5 VID pins. The VID codes are defined
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by Intel in documents titled
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"VRM X.X DC-DC Converter Design Guidelines".
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(VRM = Voltage Regulator Module)
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These documents are available at http://developer.intel.com.
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There are several different VRM document versions.
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The common versions are as follows:
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Document Version Voltage Range Increment Processors
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---------------- ------------- --------- ----------
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"2.4" 0.8 - 1.55 0.025V AMD Opteron 24x
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8.2 (8.1, 8.3) 1.30 - 2.05V 0.05V PII, PIII, Celeron
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2.1 - 3.5V 0.10V
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8.4 1.30 - 2.05V 0.05V PIII, Celeron
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4 pins only
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8.5 1.050 - 1.825V 0.05V PIII-S Tualatin
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9.0, (9.1) 1.100 - 1.850V 0.025V P4, AMD Socket A
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"2.4" is not an actual document version but simply a way to identify
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AMD Opteron 24x processors.
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Note that versions 8.1 - 8.4 are compatible.
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lm_sensors versions through 2.6.3 support only the VRM 8.2 standard.
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Starting in lm_sensors 2.6.4 the VRM version is configurable.
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To configure the sensor chip for the correct voltage range,
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you must set the "vrm" correctly either via /proc or sensors.conf.
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To be compatible with previous lm_sensors versions, the vrm defaults
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to version 8.2.
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To change the vrm version to 9.0, for example, do the following
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after the chip module (in this example, w83781d) is loaded:
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echo 9.0 > /proc/sys/dev/sensors/w83781d-isa-0290/vrm
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Alternatively, add a line in /etc/sensors.conf in the w83781d section:
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set vrm 9.0
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and then, after the chip module is loaded, do:
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sensors -s
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After this, reading the vid either by
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cat /proc/sys/dev/sensors/w83781d-isa-0290/vid
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or by
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sensors
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should show the new vid value.
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The following values are legal vrm values:
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8.2, 8.4, 8.5, 9.0
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Remember, the VID pins on the sensor chips are inputs only.
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That means they can't be changed and there shouldn't be
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any problems if you experiment with the vrm values until you
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get it right.
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Not all sensor chips have VID inputs.
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For those that do, the VRM support status is listed below.
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The following chip drivers support all the VRM versions via
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/etc/sensors.conf and the vrm entry in /proc:
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adm1025, w83781d, lm87
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The following chip drivers support only VRM 8.2 and cannot be changed:
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adm1024, it87, mtp008
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adm9240, gl520sm, lm78, maxilife
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If you have a board with one of these chips which needs advanced
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VRM support please email us.
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