Based on kernel version 4.0. Page generated on 2015-04-14 21:24 EST.
1 Kernel driver via686a 2 ===================== 3 4 Supported chips: 5 * Via VT82C686A, VT82C686B Southbridge Integrated Hardware Monitor 6 Prefix: 'via686a' 7 Addresses scanned: ISA in PCI-space encoded address 8 Datasheet: On request through web form (http://www.via.com.tw/en/resources/download-center/) 9 10 Authors: 11 Kyösti Mälkki <firstname.lastname@example.org>, 12 Mark D. Studebaker <email@example.com> 13 Bob Dougherty <firstname.lastname@example.org> 14 (Some conversion-factor data were contributed by 15 Jonathan Teh Soon Yew <email@example.com> 16 and Alex van Kaam <firstname.lastname@example.org>.) 17 18 Module Parameters 19 ----------------- 20 21 force_addr=0xaddr Set the I/O base address. Useful for boards that 22 don't set the address in the BIOS. Look for a BIOS 23 upgrade before resorting to this. Does not do a 24 PCI force; the via686a must still be present in lspci. 25 Don't use this unless the driver complains that the 26 base address is not set. 27 Example: 'modprobe via686a force_addr=0x6000' 28 29 Description 30 ----------- 31 32 The driver does not distinguish between the chips and reports 33 all as a 686A. 34 35 The Via 686a southbridge has integrated hardware monitor functionality. 36 It also has an I2C bus, but this driver only supports the hardware monitor. 37 For the I2C bus driver, see <file:Documentation/i2c/busses/i2c-viapro> 38 39 The Via 686a implements three temperature sensors, two fan rotation speed 40 sensors, five voltage sensors and alarms. 41 42 Temperatures are measured in degrees Celsius. An alarm is triggered once 43 when the Overtemperature Shutdown limit is crossed; it is triggered again 44 as soon as it drops below the hysteresis value. 45 46 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is 47 triggered if the rotation speed has dropped below a programmable limit. Fan 48 readings can be divided by a programmable divider (1, 2, 4 or 8) to give 49 the readings more range or accuracy. Not all RPM values can accurately be 50 represented, so some rounding is done. With a divider of 2, the lowest 51 representable value is around 2600 RPM. 52 53 Voltage sensors (also known as IN sensors) report their values in volts. 54 An alarm is triggered if the voltage has crossed a programmable minimum 55 or maximum limit. Voltages are internally scalled, so each voltage channel 56 has a different resolution and range. 57 58 If an alarm triggers, it will remain triggered until the hardware register 59 is read at least once. This means that the cause for the alarm may 60 already have disappeared! Note that in the current implementation, all 61 hardware registers are read whenever any data is read (unless it is less 62 than 1.5 seconds since the last update). This means that you can easily 63 miss once-only alarms. 64 65 The driver only updates its values each 1.5 seconds; reading it more often 66 will do no harm, but will return 'old' values. 67 68 Known Issues 69 ------------ 70 71 This driver handles sensors integrated in some VIA south bridges. It is 72 possible that a motherboard maker used a VT82C686A/B chip as part of a 73 product design but was not interested in its hardware monitoring features, 74 in which case the sensor inputs will not be wired. This is the case of 75 the Asus K7V, A7V and A7V133 motherboards, to name only a few of them. 76 So, if you need the force_addr parameter, and end up with values which 77 don't seem to make any sense, don't look any further: your chip is simply 78 not wired for hardware monitoring.