On Sun, 18 Nov 2007 16:57:22 +0100, Alexander Kiel wrote: > Hi Jean, > > > > Ok the problem with pwmconfig is the following: > > > > > > echo 0 > $ENABLE 2> /dev/null outputs actually 0. This is the 0 from the > > > echo. echo 3 > $ENABLE 2> /dev/null would output 3. I have no clue why > > > this is the case. > > > > How did you try that, on the command line? $ENABLE is a variable in the > > pwmconfig script, on the command line it's undefined, so that can't > > work. Your original report doesn't show any "0" printed on the screen. > > Yes I did this on the command line (bash). Of course, I replaced the > $ENABLE variable through pwm1_enable. Try the following command > in /sys/class/hwmon/hwmon0/device as root: > > echo 255 > pwm1; echo 0 > pwm1_enable 2>/dev/null; echo 1 > pwm1_enable > 2>/dev/null; echo 255 > pwm1; cat pwm1 > > This gives me a 0 on the stdout. But this: > > echo 255 > pwm1; echo 0 > pwm1_enable >/dev/null 2>/dev/null; echo 1 > > pwm1_enable 2>/dev/null; echo 255 > pwm1; cat pwm1 > > gives me 255 on stdout. May I ask what shell (and version) you're using? Both sequences above return 255 here. > > PWM1 has no fan attached in my configuration. It may be the CPU fan > controller, but I don't have a CPU fan, I have water cooling. I don't > know if this makes a difference. Currently I have pwm4 working by BIOS > (ASUS Q-fan control). PWM1 has no fan attached on my system either. > > > > This 0 causes the line echo $MAX > $1 to set pwm1 to 0 instead of 255. > > > > I very much doubt it. Both statements are separate, I fail to see how > > whatever the first one does could have any influence on the second. > > I don't have much experience in shell programming. But is it possible > that the 0 at stdout stays there until the next command? And than the > cat 255 > pwm1 would be a echo 0 255 > pwm1. It would take a broken shell to do what you describe, if that's possible at all. The following command should answer your question: echo 0 > /sys/class/hwmon/hwmon0/device/pwm1_enable ; echo 255 > /tmp/pwm1 ; cat /tmp/pwm1 Here, it prints the expected error message, then 255. > > > > If I add a > /dev/null to the line echo 0 > $ENABLE 2> /dev/null it > > > works as it should. > > > > > > So the diff is: > > > ---------------------------------------------------------------------- > > > 127c127 > > > < echo 0 > $ENABLE > /dev/null 2> /dev/null > > > --- > > > > echo 0 > $ENABLE 2> /dev/null > > > ---------------------------------------------------------------------- > > > > > > Can you submit this patch? I don't have a reasonable access to the > > > lm-sensors community. > > > > This patch is not correct, it breaks pwmconfig more than it fixes it. > > I have pwmconfig v0.8. Maybe the line numbers are not correct in your > version. I think you will find the right position per hand. a additional > > /dev/null should not hurt. I meant that the patch is functionally incorrect, not that I was not able to apply it (although it is, indeed, technically incorrect, for it's reverted and not in unified format.) An additional > /dev/null can certainly hurt, as it overwrites the previous > $ENABLE, meaning that you do NOT write the value to the sysfs file at all. It doesn't make a difference for you because writing 0 to pwm1_enable doesn't actually work with the w83627ehf driver, but your change breaks drivers for which it works. > > > As explained above, the problem you have is not with setting > > pwm1_enable to 1 (that works) but presumably with setting pwm1 to 255. > > So you're trying to fix the wrong line of the script. > > Yes the problem is setting pwm1 to 255. But it is set to 0 by pwmconfig > v0.8. And after my investigation I find out that the 0 comes from this > echo 0 statement. I than fixed pwmconfig with this additional > > /dev/null and it worked for me. It worked completely. It found my fan > attached to pwm4 and all this stuff. -- Jean Delvare
