Greetings,
Jean Delvare and myself have been working on an algorithm for
automatically setting fan clock divider, to solve the issue of users
not being able to read their fan speed. Being a newcomer I too had
this problem and took some time to pick up what the requirements
needed to be.
These results obtained from adm9240 driver, which is just about
ready for yet another posting :) Something has to 'give' when user
enters silly minimum fan limit, yesterday I finally appreciated this
aspect and today I fix driver and provide these test results.
Notice fan limits above a certain point are pulled back? that is due
to the adjustment required to bring the system back to a point where
it can give the user fan speed measurements. In this case, the test
box has a fan needing a minimum fan clock divide by four. So on very
high limit settings, it requires two measurement cycles to 'repair'
the fan clock divider.
Requirements:
automatic fan clock divider
````````````````````````````
* User sets 0 to fan_min limit
- low speed alarm is disabled
- fan clock divider not changed
- auto fan clock adjuster disabled
* User sets fan_min limit too low
- low speed alarm is enabled
- fan clock divider set to max
- fan_min set to register value 254 which corresponds
to 664 rpm on adm9240
- low speed alarm will be asserted if fan speed is
less than minimum measurable speed
- auto fan clock adjuster disabled (by virtue fan_div == max)
* User sets reasonable fan speed
- low speed alarm is enabled
- fan clock divider set to suit fan_min
- auto fan clock adjuster enabled
* User sets unreasonably high low fan speed limit
- resolution of the low speed limit may be reduced
- alarm will be asserted
- fan speed may be displayed as zero until the auto fan
clock divider adjuster brings fan speed clock divider
back into chip measurement range, this will occur
within a few measurement cycles.
results
````````
Grant's auto fan_div tester...
fan_min fan rpm fan_min fan rpm alarm
set retry read read state
-------- ------- -------- -------- -----
400 664 1577
500 664 1591
600 664 1591
652 664 1591
654 664 1577
657 664 1577
659 664 1577
662 664 1577
664 664 1577
667 666 1577
870 869 1577
874 874 1591
879 878 1577
884 883 1591
888 888 1577
1303 1298 1577
1308 1308 1591
1313 1308 1591
1318 1318 1577
1324 1318 1591
1329 1328 1577
1334 1328 1577
1740 1739 1591 alarm
1749 1739 1577 alarm
1758 1757 1569 alarm
1767 1767 1577 alarm
1776 1776 1584 alarm
2606 2596 1584 alarm
2616 2616 1577 alarm
2626 2616 1584 alarm
2637 2636 1577 alarm
2647 2636 1569 alarm
2657 2657 1577 alarm
2668 2657 1577 alarm
3479 3479 1584 alarm
3497 3479 1584 alarm
3516 * 3515 1577 alarm
3534 * 3515 1584 alarm
3553 * 3552 1591 alarm
5212 * 5192 1584 alarm
5233 * 5192 1577 alarm
5253 * 5273 1584 alarm
5273 * 5273 1577 alarm
5294 * 5273 1577 alarm
5315 * 5273 1577 alarm
5336 * 5357 1577 alarm
6959 * 6887 1577 alarm
6995 ** 7031 1584 alarm
7031 ** 7031 1584 alarm
7068 ** 7031 1577 alarm
7105 ** 7031 1577 alarm
10000 ** 9926 1577 alarm
25000 ** 24107 1577 alarm
50000 ** 48214 1584 alarm
100000 ** 84375 1584 alarm
250000 ** 168750 1584 alarm
500000 ** 337500 1591 alarm
1000000 ** 337500 1584 alarm
2500000 ** 337500 1591 alarm
5000000 ** 337500 1584 alarm
10000000 ** 337500 1577 alarm
The asterisks show how many extra measurement cycles the test program
had to wait for non-zero fan speed rpm reading.
/var/log/debug
```````````````
adm9240 0-002d: fan1 low limit set fan speed 1196 <<== set limits
adm9240 0-002d: fan1 clock divider changed from 4 to 8
adm9240 0-002d: fan2 low limit set disabled
adm9240 0-002d: fan1 low limit set minimum 664 <<== start test
adm9240 0-002d: fan1 low limit set fan speed 666
adm9240 0-002d: fan1 low limit set fan speed 869
adm9240 0-002d: fan1 low limit set fan speed 874
adm9240 0-002d: fan1 low limit set fan speed 878
adm9240 0-002d: fan1 low limit set fan speed 883
adm9240 0-002d: fan1 low limit set fan speed 888
adm9240 0-002d: fan1 low limit set fan speed 1298
adm9240 0-002d: fan1 low limit set fan speed 1308
adm9240 0-002d: fan1 low limit set fan speed 1308
adm9240 0-002d: fan1 low limit set fan speed 1318
adm9240 0-002d: fan1 low limit set fan speed 1318
adm9240 0-002d: fan1 low limit set fan speed 1328
adm9240 0-002d: fan1 low limit set fan speed 1328
adm9240 0-002d: fan1 low limit set fan speed 1739
adm9240 0-002d: fan1 low limit set fan speed 1739
adm9240 0-002d: fan1 low limit set fan speed 1757
adm9240 0-002d: fan1 clock divider changed from 8 to 4
adm9240 0-002d: fan1 low limit set fan speed 1767
adm9240 0-002d: fan1 low limit set fan speed 1776
adm9240 0-002d: fan1 low limit set fan speed 2596
adm9240 0-002d: fan1 low limit set fan speed 2616
adm9240 0-002d: fan1 low limit set fan speed 2616
adm9240 0-002d: fan1 low limit set fan speed 2636
adm9240 0-002d: fan1 low limit set fan speed 2636
adm9240 0-002d: fan1 low limit set fan speed 2657
adm9240 0-002d: fan1 low limit set fan speed 2657
adm9240 0-002d: fan1 low limit set fan speed 3479
adm9240 0-002d: fan1 low limit set fan speed 3479
adm9240 0-002d: fan1 low limit set fan speed 3515
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4 <<== driver adjusts so
adm9240 0-002d: fan1 low limit set fan speed 3534 fan speed can
adm9240 0-002d: fan1 clock divider changed from 4 to 2 be displayed
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 3552
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 5192
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 5232
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 5273
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 5273
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 5273
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 5314
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 5357
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 6958
adm9240 0-002d: fan1 clock divider changed from 4 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 7031
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2 <<== driver bumps fan
adm9240 0-002d: fan1 clock divider changed from 2 to 4 clock divider
adm9240 0-002d: fan1 low limit set fan speed 7031 twice now
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 7068
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 7105
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 10000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 25000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 50000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 103846
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 270000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 675000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 1350000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 1350000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 1350000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
adm9240 0-002d: fan1 low limit set fan speed 1350000
adm9240 0-002d: fan1 clock divider changed from 4 to 1
adm9240 0-002d: fan1 clock divider changed from 1 to 2
adm9240 0-002d: fan1 clock divider changed from 2 to 4
test script
````````````
We have one list of interesting register values that are converted
to corresponding rpm values, plus another list to test response to
extremes.
peetoo:0-002d$ cat /usr/local/bin/zx-test-fan-div
#!/bin/bash
#
# test auto fan clock divider algorithm
#
# Copyright (C) 2005 Grant Coady <gcoady at gmail.com>
#
# GPLv2 per linux/COPYING by reference
#
almpath="/sys/bus/i2c/devices/0-002d/alarms"
minpath="/sys/bus/i2c/devices/0-002d/fan1_min"
fanpath="/sys/bus/i2c/devices/0-002d/fan1_input"
# values are register equivalents for interesting points:
values=(190 191 192 193 194 253 254 255 256 257 258 259)
skip_values=0
if [ "$1" == 's' ]; then
skip_values=1
fi
function test_two ()
{
local y=0
if [ $skip_values -eq 0 ]; then
for fan_div in 1 2 4 8; do
while [ $y -lt 12 ]; do
fan_limit=$(( (1350000\
+ ($fan_div * ${values[${y}]}) / 2)\
/ ($fan_div * ${values[${y}]}) ))
echo -e "$fan_limit" >> "$TMPFILE"
(( y++ ))
done
y=0
done
fi
while read fan_limit rest; do
echo -e "$fan_limit" >> "$TMPFILE"
done<<-EOF
400
500
600
10000
25000
50000
100000
250000
500000
1000000
2500000
5000000
10000000
EOF
sort -n < "$TMPFILE" | uniq > "$TMPFILE.sort"
# now we can perform test and display some answers
echo " fan_min fan rpm fan_min fan rpm alarm"
echo " set retry read read state"
echo " -------- ------- -------- -------- -----"
while read fan_limit rest; do
printf "%10d" $fan_limit
echo $fan_limit > "$minpath"
retry=4
sleep 1
read fan_rpm < "$fanpath"
echo -e " \c"
while [ $fan_rpm -eq 0 -a $retry -gt 0 ]; do
echo -e "*\c"
sleep 2
read fan_rpm < "$fanpath"
(( retry-- ))
done
while [ $retry -gt 0 ]; do
echo -e " \c"
(( retry-- ))
done
echo -e " \c"
read fan_lmt < "$minpath"
printf "%10d" $fan_lmt
printf "%10d" $fan_rpm
read alarms < "$almpath"
alarms=$(( alarms & 64 ))
if [ $alarms -gt 0 ]; then
echo -e " alarm\c"
fi
echo
sleep 1
done < "$TMPFILE.sort"
}
TMPFILE=$(mktemp -t xyz.XXXXXX)
echo -e "\nGrant's auto fan_div tester...\n"
test_two
rm -f $TMPFILE
rm -f $TMPFILE.sort
exit
#end
Read to the end? Green elephant stamp :o)
Cheers,
Grant.
