On Fri, 05 Jan 2007 23:50:28 +0100 Rudolf Marek <r.marek at assembler.cz> wrote: RM> You can use also following commands to reprogram the fans to manual mode: RM> RM> http://www.analog.com/en/prod/0,2877,ADT7470,00.html RM> RM> CHeck page 23 of datasheet. Before doing this I decided to try to read the speeds of the fans, as explained on the page 21 of the above document: # i2cget -y 0 0x2e 0x2a 0x80 # i2cget -y 0 0x2e 0x2b 0x0a # i2cget -y 0 0x2e 0x2c 0xff # i2cget -y 0 0x2e 0x2d 0xff # i2cget -y 0 0x2e 0x2e 0x6a # i2cget -y 0 0x2e 0x2f 0x0c # i2cget -y 0 0x2e 0x30 0x0a # i2cget -y 0 0x2e 0x31 0x0e Using the rule Fan Speed (RPM) = (90,000 ? 60)/Fan Tach Reading from the datasheet this corresponds to speeds 2000, 1700 and 1500 RPM and the 2 last ones must correspond to the case fans (I've thrown away the old ones and the new ones are spec'd at 1600 and 1400 RPMs respectively), As I don't have any other case fans, I think the first one must be the CPU fan (although no idea which one), it's not unreasonable for it to turn at 2000 RPMs. Just in case it can be useful to someone else, here is a script showing the fans speeds: http://www.tt-solutions.com/vz/hardware/tyan2696/fanspeed RM> Register 0x68 0x69 are controlling the manual/auto mode RM> Registers 0x32-0x34 controls the duty cycle. RM> RM> This sequence will put the chip into manual mode (first two lines) RM> Last 4 lines set the duty cycle to 50%. This should shut up the fans. RM> RM> i2cset -y 0 0x2e 0x68 0x0 RM> i2cset -y 0 0x2e 0x69 0x0 RM> i2cset -y 0 0x2e 0x32 0x80 RM> i2cset -y 0 0x2e 0x33 0x80 RM> i2cset -y 0 0x2e 0x34 0x80 RM> i2cset -y 0 0x2e 0x35 0x80 RM> RM> Inspect the fans to see if they are still spinning sufficiently after this! Changing 0x69 doesn't seem to do anything. Changing 0x68 clearly does work, before 0x32 is written the fan 0 spins up to more than 4000 RPMs. Interestingly enough setting 0x32 to low values, and even 0, doesn't decrease the fan speed below 2000RPMs anyhow. But setting it to high values does increase the speed. So it looks like there is indeed enough useful functionality to write the driver, now the only question is to find time to do it... RM> Hope it helps for a start. In fact what *really* helped was to change the fans. The new ones are silent enough even at max speed. Of course, now the question is whether they're fast enough to cool the case sufficiently but I won't know this until the summer. Thanks again for your help, VZ
