Re: [PATCH v3 3/4] arm64: dts: apple: t8103: Add i2c nodes

On 2021年11月26日 0:50:28 JST, Linus Walleij [off-list ref] wrote:

On Wed, Nov 24, 2021 at 6:42 AM Hector Martin [off-list ref] wrote:

quoted

Pulling down an I2C bus between transactions is not legal; the idle
state has to be high.

Oh right.

quoted

Apple are actually not very good at configuring GPIOs for power saving;
e.g. the I/Os for that unused i2c bus still have their input buffers
turned on, which is a waste of power. If they wanted to save the
smallest drop of power they'd turn that off. But the effect of this is
so trivial it probably makes no difference in the context of a laptop,
nevermind a desktop like the Mac Mini.

Hm that's true. The saying is that 99% is the backlight, the remaining 1% isn't
so significant after that.

From watching a USB power meter plugged into the MacBook Air, I can say the backlight is about 70% :-)

Then again, the new MBPs have LED matrix backlit screens... so suddenly dark themes are more efficient again! I should measure that one, see how much power changing themes saves.

-- 
Hector Martin "marcan" (marcan@marcan.st)
Public key: https://mrcn.st/pub