Hi David, > I understand the problem now. In the w83627ehf driver, there is this code: > static ssize_t > store_pwm_enable(struct device *dev, struct device_attribute *attr, > const char *buf, size_t count) > > ... > > if (!val || (val > 2)) /* only modes 1 and 2 are supported */ > return -EINVAL; > > That is the "write error: invalid argument" error. The reason this > code rejects a write of 0 to pwm_enable is because the w83627ehf does > not have a true "disable" mode. Some other chips will set the pwm > output to 100% when they are disabled. The w83627ehf doesn't have a > disable mode. Of course, setting it to manual and storing 255 in the > pwm would do the same thing. > > That's what pwmconfig (lm_sensors version 2.10.4) does: > # Try pwmN_enable=0 > echo 0 > $ENABLE 2> /dev/null > if [ "`cat $ENABLE`" -eq 0 ] > then > # Success > return 0 > fi > > # It didn't work, try pwmN_enable=1 pwmN=255 > echo 1 > $ENABLE 2> /dev/null > echo $MAX > $1 > if [ "`cat $ENABLE`" -eq 1 -a "`cat $1`" -ge 190 ] > then > # Success > return 0 > fi > > So I *think* the problem is in pwmconfig. But yes, manually writing 0 > to pwm_enable will give you an -EINVAL. > > To be completely honest, I haven't run pwmconfig in a while. I know it > generally works, but someone should probably post a patch to get it to > work smoothly with w83627ehf and w83627dhg chips. (I could do that... > given lots of time :-) 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. This 0 causes the line echo $MAX > $1 to set pwm1 to 0 instead of 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. Second: Can you please tell me what echo 2 > pwm1_enable does on this chip? Is it an chip automatic fan control? It works great for me. It puts my fan currently to a 155. Regards Alex
