Re: [PATCH 2/2] iwlwifi: add power management support -v2

[Dan Williams <dcbw@redhat.com>]

On Mon, 2007-11-26 at 19:11 +0200, Tomas Winkler wrote:
> On Nov 26, 2007 6:18 PM, Miguel Bot=C3=B3n <mboton.lkml@gmail.com> wr=
ote:
> >
> > On Saturday 17 November 2007 07:15:05 Tomas Winkler wrote:
> > > Why power management shouldn't be enabled while in AC? The semant=
ic of this
> > > ioctls is quite unclear.
> >
> I
> > IWL_POWER_AC and IWL_POWER_BATTERY are just two power modes. IWL_PO=
WER_AC
> > would be the default power mode when we're in AC (no power saving) =
and
> > IWL_POWER_BATTERY would be the default power mode when we're in bat=
tery
> > (power saving mode). That's why we set IWL_POWER_ENABLED flag with
> > IWL_POWER_BATTERY, because it is the only power mode that saves pow=
er.
> >
> > We can change to IWL_POWER_BATTERY or IWL_POWER_AC in any moment.
> >
> > This patch, depending if power management is enabled or not, sets w=
hich power
> > mode we should use, Then, it checks if we're already using this mod=
e or not.
> >
> I'm not sure who introduced this names (lazy to look to history) but
> that's very misleading. Nothing says that while in
> AC we cannot do power saving and vice versa. This naming is scattered
> all over the code, there should be only one place where AC and BATTER=
Y
> are  translated into appropriate (maybe configurable) power levels. W=
e
> have 5 power levels defined for iwlwifi.

At some point everyone needs to standardize on power levels so that
userland has a hope of mapping the right state to the right power level
in the driver.  Otherwise, we get into a situation where broadcom power
levels don't map the same way iwl powerlevels do, and then we can't eve=
r
do the right thing.

dan

> Tomas
>=20
> > --
> >        Miguel Bot=C3=B3n
> >
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