On Friday 27 May 2016 14:11:11 Gabriele Mazzotta wrote: > On 22/05/2016 13:50, Pali Rohár wrote: > > This patch exports standard hwmon pwmX_enable sysfs attribute for enabling > > or disabling automatic fan control by BIOS. Standard value "1" is for > > disabling automatic BIOS fan control and value "2" for enabling. > > > > Currently there is no way to check if BIOS auto mode is enabled (at least > > it is not know how to do it), so hwmon sysfs attribute is write-only. > > > > By default BIOS auto mode is enabled by laptop firmware. > > > > When BIOS auto mode is enabled, custom fan speed value (set via hwmon pwmX > > sysfs attribute) is overwritten by SMM in few seconds and therefore any > > custom settings are without effect. So this is reason why implementing > > option for disabling BIOS auto mode is needed. > > > > So finally this patch allows kernel to set and control fan speed on > > laptops, but it can be dangerous (like setting speed of other fans). > > > > This new feature is highly experimental, uses Dell SMM calls, so does not > > have to be supported by all laptops BIOSes. It was tested on Dell Latitude > > E6440 with BIOS A5. > > Tested on a Dell XPS13 9333. Changing the value of pwm1_enable appears > to have no effect here.
Can you check what i8k_enable_fan_auto_mode() returns? Error code or not? -- Pali Rohár [email protected]
