Auto Fan Control Plug-in Assumes Optional PWM Enable SysFS Attribute Exists

[Stonyx]

The Auto Fan Control plug-in is hard coded to look for the pwmX_enable sysfs attribute, however, this is an optional attribute. For example, we're working on developing a driver for a embedded controller chip used in many QNAP NAS devices so that Unraid and other Linux based OSes can read and control fan speeds, however, this embedded controller chip doesn't provide a enable/disable PWM function (PWM is always enabled) therefore according to the hwmon/sysfs standards our driver should not be creating a PWM enable sysfs attribute. However, without that attribute we get the following error from the Auto Fan Control plugin:

<br /><b>Warning</b>:  file_get_contents(/sys/devices/platform/qnap-ec/hwmon/hwmon2/pwm7_enable): failed to open stream: No such file or directory in <b>/usr/local/emhttp/plugins/dynamix.system.autofan/include/SystemFan.php</b> on line <b>40</b><br /><br /><b>Warning</b>:  file_put_contents(/sys/devices/platform/qnap-ec/hwmon/hwmon2/pwm7_enable): failed to open stream: Permission denied in <b>/usr/local/emhttp/plugins/dynamix.system.autofan/include/SystemFan.php</b> on line <b>42</b><br /><br /><b>Warning</b>:  file_put_contents(/sys/devices/platform/qnap-ec/hwmon/hwmon2/pwm7_enable): failed to open stream: Permission denied in <b>/usr/local/emhttp/plugins/dynamix.system.autofan/include/SystemFan.php</b> on line <b>50</b><br />

Is it possible to change the plug-in to check if this attribute exists before trying to open it and if it doesn't exist assume PWM is enabled? Or is the concern that without this attribute the plug-in doesn't know if PWM is enabled and the developers don't feel comfortable assuming that it is enabled?

[ssbarnea]

Haha, that's fun as I faced this issue myself today.

# ls -1   /sys/class/hwmon/hwmon4/
fan1_input
fan34_input
fan35_input
fan7_input
name
pwm1
pwm34
pwm7
subsystem@
temp1_input
temp6_input
temp7_input
temp8_input
uevent

Enabling and disabling is done by directly writing to pwm* ones.

[MrAungThuHtet]

The Auto Fan Control plug-in is hard coded to look for the pwmX_enable sysfs attribute, however, this is an optional attribute. For example, we're working on developing a driver for a embedded controller chip used in many QNAP NAS devices so that Unraid and other Linux based OSes can read and control fan speeds, however, this embedded controller chip doesn't provide a enable/disable PWM function (PWM is always enabled) therefore according to the hwmon/sysfs standards our driver should not be creating a PWM enable sysfs attribute. However, without that attribute we get the following error from the Auto Fan Control plugin:

<br /><b>Warning</b>:  file_get_contents(/sys/devices/platform/qnap-ec/hwmon/hwmon2/pwm7_enable): failed to open stream: No such file or directory in <b>/usr/local/emhttp/plugins/dynamix.system.autofan/include/SystemFan.php</b> on line <b>40</b><br /><br /><b>Warning</b>:  file_put_contents(/sys/devices/platform/qnap-ec/hwmon/hwmon2/pwm7_enable): failed to open stream: Permission denied in <b>/usr/local/emhttp/plugins/dynamix.system.autofan/include/SystemFan.php</b> on line <b>42</b><br /><br /><b>Warning</b>:  file_put_contents(/sys/devices/platform/qnap-ec/hwmon/hwmon2/pwm7_enable): failed to open stream: Permission denied in <b>/usr/local/emhttp/plugins/dynamix.system.autofan/include/SystemFan.php</b> on line <b>50</b><br />

Is it possible to change the plug-in to check if this attribute exists before trying to open it and if it doesn't exist assume PWM is enabled? Or is the concern that without this attribute the plug-in doesn't know if PWM is enabled and the developers don't feel comfortable assuming that it is enabled?