Hi Rudolf, > > * Reading the F71805F documentation, I learned that the external > > circuitery needed for PWM fan speed control is completely different > > from the one needed for DC fan speed control. So I wonder if it is a > > good idea to let the user change between the two modes. Clearly the > > BIOS should set it right. I tried to switch to DC mode and it had no > > effect at all on my fan (not even on/off). I wonder if it is possible > > to confuse or even damage the hardware by using the wrong mode? > > Yes DC/PWM settings were already removed from W83793 and imho not implemented on > EHF too. Well, I have no problem with chip makers implementing both and letting the integrators choose what they want to do. But in that case the BIOS should set the proper operation mode. > You need to know what circuits are onboard -> BIOS should do that for you. If > you want to implement this I would suggest just a kernel param for BIOS fixups. I usually avoid adding BIOS fixups unless really needed. I don't want to incite motherboard manufacturers to ship broken BIOSes. As long as nobody reports a problem with this, I won't implement it. And even then, I'd rather ask the user to request a fixed BIOS, as it makes much more sense. So my current plan is: * Provide pwmN_mode, but read-only. * Only provide pwmN_freq in PWM mode. Thanks, -- Jean Delvare
