On Mon 2018-06-18 04:48:32, Tony Lindgren wrote: > * Pavel Machek <pavel@xxxxxx> [180618 09:37]: > > On Mon 2018-06-18 01:28:58, Tony Lindgren wrote: > > > * Pavel Machek <pavel@xxxxxx> [180618 07:43]: > > > > > > > > So... there are mA, mAh values. Those come from hardware, and I > > > > believe we should keep them. > > > > > > > > But there are also mW, mWh values, which are synthetic. Userland can > > > > compute them from mV, mA values... and it is confusing that kernel > > > > provides them. (My tendency was to start computing these synthetic > > > > values in userland, to compare them with "real hardware" values from > > > > kernel. But then I looked at kernel implementation, and realized they > > > > are synthetic, tooo...) > > > > > > Hmm mWh value is based on the hardware sampled shunt > > > values and number of samples gathered between the > > > two readings. I'd rather call the calculated values > > > based on userland reading mV and mA values "synthetic" :) > > > > As far as I know, shunt resistors provide you with current (mA) not > > power (mW) measurement... and cpcap-battery computes power_now as > > voltage * current. I'd rather have kernel tell me "hardware can't > > measure power" and do "voltage*current" computation in userspace. > > Yup you are correct the hardware samples mA and we still need > to calculate mW based on the voltage. > > But considering it works and seems to match the power supply > provided average power consumption numbers pretty well and at > least I'm using it.. What is your reasoning for removing such > a usable interface? Well, it is confusing for the userland, because it has no way of knowing data is synthetic. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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