Youtuber Brad Ling found out about this in his recent livestream that the module cards being plugged in draw significant amounts of power without anything actually being connected to them at 2:27:00. Could there be a fix for this in the future?
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I’m wondering high power draw from some modules could be one possible symptom of this linked issue. These exact symptoms aren’t described on that page, but I could totally imagine a scenario where if that EMI sticker was shorting the particular wrong pins it could high power draw when some modules are connected.
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This is possibly the same issue Michael Wu is reporting earlier in this thread where the HDMI Expansion Card was keeping the retimer active, which we are investigating.
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Anecdotally I noticed some substantial power savings swapping out my HDMI and USB-A for usb-c cards as well, on the order of 700 mW idle. Not I did not notice this in powertop, only by removing the card.
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Ditto to @Michael_Lingelbach 's experience, my HDMI card shows ~900mW draw and for some reason 100% usage on powertop. Possibly interestingly, before plugging in to an external monitor for the first time, the HDMI card if it drew any power was <200 micro-Watts (low enough it did not show in the top ~60 entries in powertop).
Perhaps to someone better versed in the technical details this is a clue to some sort of toggle that may have been tripped during the first HDMI usage that can maybe be un-tripped afterward to save a few joules here and there? Whatever the initial configuration was, it worked fine for recognizing the outputting to the external monitor on first use.
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It seems that the retimer on the mainboard is not re-entering the low power state that it should be when nothing is plugged in. We’re digging into why that is.
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By the way, as others have reported, with a combination of, in my case, auto-cpufreq and tlp (and not having the HDMI card installed), I was able to get down to 5-6W idle, 7-8W doing light web browsing and so forth.
As an experiment I disabled hyperthreading (and while I was at it, side-channel attack mitigations), and it got down to a little over 4W while idle. Since I don’t need the extra horsepower, this is seeming like a good tradeoff for me, so I’ll keep running it and see how it looks.
Of course, in a perfect world I’d undervolt, but… thanks Intel!
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@Brett_Kosinski That’s actually pretty high, mine idles closer to 3.5W (but 8W seems about right for firefox or video streaming)
I’m seeing 9.9 while viewing this page in Chrome and screen at 1/2 brightness. I don’t have the display cards in. I do have two of the USB-C, one USB-A and one 250gb installed.
What happens if you turn screen brightness down? The backlight is a huge power draw and when I’m assessing my battery tuning, I’m running with the screen at usually the second or third lowest setting.
I don’t know about you, but when I put the laptop to sleep I don’t expect it maintaining an internet connection with anything. As such I disabled connected standby to disconnected standby. I’d recommend it to you, as it will save power in standby as well.
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So the Suspended message on the battery report doesn’t mean its shut down? I was under the impression it somehow drained the battery while it was shut down
Dropping it from 1/2 brightness to 1/4 brightness in the gnome panel dropped me to 2.5W rate while on this page in Chrome!
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One issue I’ve noticed is high audio codec power draw while watching video. This seems a little higher than I would expect for an mkv/AAC local filed played via mpv on pipewire
The battery reports a discharge rate of 9.44 W
The energy consumed was 206 J
System baseline power is estimated at 11.9 W
Power est. Usage Device name
4.50 W 24.8% Display backlight
3.21 W 53.0% CPU misc
1.81 W 8.7 pkts/s Network interface: wlp170s0 (iwlwifi)
1.56 W 100.0% Audio codec hwC0D0: Realtek
784 mW 53.0% CPU core
Suspending a laptop does not shut it down. Rather it puts the components into a lower power state, and keeps power to the RAM so that your current session is retained. This is why when you lift the lid again, your session is immediately restored.
When your computer is shut down, all power is cut and the system is truly off. You will need to turn it on and the system will boot again.
So if your network adapter (wireless card) is continuing to receive power to maintain a wireless connection it is using more power than if it was not powered during standby.
When you considered that just maintaining a wireless connection is pointless if traffic received couldn’t be actioned, and so connected standby can also wake the system to process said network traffic, leading to more power use during standby.
Hope that explanation helps.
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@kaprests I think the reason why system76’s machine has decent battery life is that their machine and software is designed in a relatively close system (they don’t actually make the machines themselves but they can do specific optimizations) this is some what similar to what apple does. An operating system designed to work just on apple devices, which gave them so much opportunity to optimize that their phones so they run extremely fast with a lot less ram and battery demands. This is less likely on systems like Linux (or it’s kid basically Android), the kernel is usually configured before compiling to work for as much devices as possible out of the box (most of the “daily driver” distros do this) Which means turning on features that some laptops simply don’t benefit from or use at all (I don’t know if this affects battery life but for example you can turn both AMD and Intel support in the kernal on even though you would most definitely use just one platform at a time). Windows happens to behave in a similar pattern but Microsoft is doing a lot more communication with the laptop manufacturers than the Linux community to ship well optimized ISOs. That’s just from what I deduced over the years and I don’t got much sources. Just food for the brain I guess.
@Runkai_Zhang Yeah! I think what you are saying is the same point that I tried to convey. Most laptops are tuned by the manufacturer to run Windows, not Linux, and so one should expect that e.g. battery life may suffer on some such devices. I used S76 as an example of manufacturer tuning their machines to run Linux, to argue that Linux is not inherently worse performing with regard to battery life, it comes more down to the hardware support/tuning.
As you say, the same holds for apple, but for iphones/ipads and recently the M1 macs they also just happen to design better chips. 
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Yeah, brightness isn’t linear. In order to give a perceivable increase in display brightness the panel needs to push itself harder.
(LED Brightness to your eye, Gamma correction – No! | HP LED Shield)
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Hearkening back to the HDMI expansion card drawing power when off, it seems I’ve stumbled upon a solution suggested by Powertop itself, which is:
echo ‘auto’ > ‘/sys/bus/usb/devices/3-6/power/control’
Empirically I don’t see the power draw in the top listing in Powertop after doing that, until I plug in an external monitor (fair enough), and it goes away after. For the moment I’m needing to do this after every boot but that is my ignorance of how to set these things persistently…
But upshot is maybe doesn’t need something rejiggered on the mainboard to at least paper over the issue?
ETA: With the change to the HDMI card power management, display brightness at about 10%, and having turned Bluetooth off, at rest seems to get ~4W draw at rest most of the time just eyeballing it. Amazed at @malachid 's result, considering the wifi is reporting 2.66W alone on mine!