On Mon, 03 Oct 2022 14:13:10 -0700, Andi Shyti wrote: > Hi Andi, > [...] > > > > diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon > > > index 16e697b1db3d..7525db243d74 100644 > > > --- a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon > > > +++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon > > > @@ -25,3 +25,11 @@ Contact: dri-devel@xxxxxxxxxxxxxxxxxxxxx > > > Description: RO. Card default power limit (default TDP setting). > > > > > > Only supported for particular Intel i915 graphics platforms. > > > + > > > +What: /sys/devices/.../hwmon/hwmon<i>/energy1_input > > > +Date: February 2023 > > > +KernelVersion: 6.2 > > > +Contact: dri-devel@xxxxxxxxxxxxxxxxxxxxx > > > > I'm sorry for being late on the review here, and I know that others > > already looked at the date and other details here in this doc. > > So I'm curious why we have decided for the dri-devel mailing list > > and not for the intel-gfx since intel-gfx is the only one we have > > listed for i915 dir in the MAINTAINERS file: > > L: intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > same question here. These have all been changed to intel-gfx. > > > > +Description: RO. Energy input of device in microjoules. > > > + > > > + Only supported for particular Intel i915 graphics platforms. > > [...] > > > > +/* > > > + * hwm_energy - Obtain energy value > > > + * > > > + * The underlying energy hardware register is 32-bits and is subject to > > > + * overflow. How long before overflow? For example, with an example > > > + * scaling bit shift of 14 bits (see register *PACKAGE_POWER_SKU_UNIT) and > > > + * a power draw of 1000 watts, the 32-bit counter will overflow in > > > + * approximately 4.36 minutes. > > > + * > > > + * Examples: > > > + * 1 watt: (2^32 >> 14) / 1 W / (60 * 60 * 24) secs/day -> 3 days > > > + * 1000 watts: (2^32 >> 14) / 1000 W / 60 secs/min -> 4.36 minutes > > > + * > > > + * The function significantly increases overflow duration (from 4.36 > > > + * minutes) by accumulating the energy register into a 'long' as allowed by > > > + * the hwmon API. Using x86_64 128 bit arithmetic (see mul_u64_u32_shr()), > > > + * a 'long' of 63 bits, SF_ENERGY of 1e6 (~20 bits) and > > > + * hwmon->scl_shift_energy of 14 bits we have 57 (63 - 20 + 14) bits before > > > + * energy1_input overflows. This at 1000 W is an overflow duration of 278 years. > > > + */ > > > +static int > > > +hwm_energy(struct hwm_drvdata *ddat, long *energy) > > This function can just be void. Done. Thanks. -- Ashutosh
