Tobias, Please answer to the mailing list rather than to me only. On Thu, 7 Dec 2006 13:09:48 +0100, Tobias Fritz wrote: > thanks for your reply. I rewrote fancontrol now and it works ok. But I'd still > be interested in a better solution. I'll contact the author of speedfan to > see if he really got it to work better or just mapped the 0-10 values to his > 0-100% settings (if there are just 10 different speeds I can set my fan to I > can live very well with the fancontrol hack. However if it is possible to set > it to more values it would be nice because right now it goes from 1500 RPM > directly to 2000 and then to 2200 and doesn't change much more after that) Yes, this is typical of an improper PWM base frequency. When I experimented with different frequencies on my own system, I drew the following graph: http://khali.linux-fr.org/devel/lm-sensors/pwm_response_curves.png As you can see, at high frequencies, the range where I could actually control the speed was really small, even though not as small as what you report on your system. > Output of the isadump: > > 0 1 2 3 4 5 6 7 8 9 a b c d e f > 00: 19 10 ff 07 37 ff 07 37 ff 07 1a 09 09 ff ff ff > 10: ff ff ff 72 87 00 01 00 00 00 00 00 00 00 00 00 > 20: 69 00 cf b1 be 00 00 af ff 2d 1b ff ff ff ff ff > 30: ff ff ff ff ff ff ff ff ff ff ff ff ff ef ff ff > 40: ff ff ff ff ff ff ff ff 2d ff ff ff ff ff ff ff > 50: ff 18 7f 7f 7f ff ff ff 90 56 fb 12 00 00 00 00 > 60: 7f 7f 7f 7f 7f 00 00 00 7f 7f 7f 7f 7f 00 00 00 > 70: 7f 7f 7f 7f 00 00 00 00 ff ff ff ff ff ff ff ff > 80: 19 10 00 00 37 ff 07 37 ff 07 1a 09 09 ff ff ff > 90: ff ff ff 72 87 00 01 00 00 00 00 00 00 00 00 00 > a0: 69 00 cf b1 be 00 00 af ff 2d 1b ff ff ff ff ff > b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ef ff ff > c0: ff ff ff ff ff ff ff ff 2d ff ff ff ff ff ff ff > d0: ff 18 7f 7f 7f ff ff ff 90 56 fb 12 00 00 00 00 > e0: 7f 7f 7f 7f 7f 00 00 00 7f 7f 7f 7f 7f 00 00 00 > f0: 7f 7f 7f 7f 00 00 00 00 ff ff ff ff ff ff ff ff So your current PWM base frequency is 48 MHz (comparing the value of bits 6-4 of register 0x14 with the IT8705F datasheet) which is the maximum value. You can use "isaset" to try different frequencies: isaset 0x295 0x296 0x14 0x00 0x70 # 24 MHz isaset 0x295 0x296 0x14 0x10 0x70 # 24 MHz isaset 0x295 0x296 0x14 0x20 0x70 # 12 MHz isaset 0x295 0x296 0x14 0x30 0x70 # 8 MHz isaset 0x295 0x296 0x14 0x40 0x70 # 6 MHz isaset 0x295 0x296 0x14 0x50 0x70 # 3 MHz isaset 0x295 0x296 0x14 0x60 0x70 # 1.5 MHz isaset 0x295 0x296 0x14 0x70 0x70 # 0.75 MHz As a rule of thumb, lower frequencies should give your better control, but you might also bring annoying sounds. Please experiment with different values and report. -- Jean Delvare
