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The values of the limit registers affect the fan speed in a particular way. Document this behaviour so that future users can exploit it if required. Signed-off-by: Armin Wolf <W_Armin@gmx.de> Link: https://lore.kernel.org/r/20230907052639.16491-6-W_Armin@gmx.de Signed-off-by: Guenter Roeck <linux@roeck-us.net>
46 lines
1.6 KiB
ReStructuredText
46 lines
1.6 KiB
ReStructuredText
Kernel driver sch5627
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=====================
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Supported chips:
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* SMSC SCH5627
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Prefix: 'sch5627'
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Addresses scanned: none, address read from Super I/O config space
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Datasheet: Application Note available upon request
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Author: Hans de Goede <hdegoede@redhat.com>
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Description
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-----------
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SMSC SCH5627 Super I/O chips include complete hardware monitoring
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capabilities. They can monitor up to 5 voltages, 4 fans and 8 temperatures.
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In addition, the SCH5627 exports data describing which temperature sensors
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affect the speed of each fan. Setting pwmX_auto_channels_temp to 0 forces
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the corresponding fan to full speed until another value is written.
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The SMSC SCH5627 hardware monitoring part also contains an integrated
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watchdog. In order for this watchdog to function some motherboard specific
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initialization most be done by the BIOS, so if the watchdog is not enabled
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by the BIOS the sch5627 driver will not register a watchdog device.
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The hardware monitoring part of the SMSC SCH5627 is accessed by talking
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through an embedded microcontroller. An application note describing the
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protocol for communicating with the microcontroller is available upon
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request. Please mail me if you want a copy.
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Controlling fan speed
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---------------------
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The SCH5627 allows for partially controlling the fan speed. If a temperature
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channel excedes tempX_max, all fans are forced to maximum speed. The same is not
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true for tempX_crit, presumably some other measures to cool down the system are
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take in this case.
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In which way the value of fanX_min affects the fan speed is currently unknown.
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