> > The user still doesn't have to care, which is fine, but if the user > > has a fan speed between 2000 and 5000 RPM, with low limit set to > > 1500 RPM, he/she will have a "bad" accuracy at 5000 RPM (+/- 104 > > RPM). I see this as the low limit "nailing" the divider ;) > > This doesn't sound so bad at all. And this seems to be the simplest > approach. Agreed. > > This is what I implemented in my new pc87360 driver (after trying > > #1). I use 85 and 224 as the arbitrary limits for changing > > dividers. > > This confused me a bit. It seems that a direct consequence of > implementation #2 is that the divider will be set in a way that the > low limit will be between 128 and 255, and that there is no point in > changing the divider, because it will only get worse. You're absolutely right. > This leads directly to implementation #4. Am I missing something? You are. In #4, the divider is arbitrarily chosen by "us", regardless of the user's setup. In #2, the divider is chosen according to the user's hardware and fan use. The common point is that (after setting the low limit for #2) the divider will no longer change (until the low limit changes for #2). But in #2 the divider is optimal, in #4 it is arbitrary. This makes a big difference because we cannot possibly arbitrarily pick a divider and not allow the user to change it, so in #4 we would have to keep the manual interface as well, as it exists for now. For #2, we can reasonably hope to get rid of the manual interface after some times (once the automatic mode will have been tested and is believed to be correct). > Anyway, if the user is really concerned about accuracy an average of > several measurements should increase precision in this kind of > problem. Yes, that's a possibility. Not sure it's even worth the extra code, but someone motivated could do it, you're right. Thanks for your comments :) -- Jean Delvare http://khali.linux-fr.org/
