Battery care support for Acer laptops - how to re-engineer?

[wojpawlik]

I own Acer SF314-43. What tools can I use to investigate how Acer Care Center
communicates with hardware?

[linrunner]

I have no idea, but I leave it open here, in case someone who reads here knows it.

[dxvsh]

@wojpawlik Hey, I have the exact same laptop! I'm running a windows/void linux dualboot and I have a curious observation to report. I limited the battery charging threshold to 80% using the acer care center and it works exactly as advertised on windows. But somehow, this setting persists even when running linux! So now, the battery stops charging at 80 even inside linux. Acer care center is just a normal windows program but strangely its setting survives across different operating systems just as if it were a bios setting.

It would be great if this gets working in tlp so people won't have to set up a dualboot just to limit the battery charge percentage. Here's hoping someone figures this one out. Good luck folks!

[Bartvelp]

Just to chime in, @dxmuses. Setting a battery charging limit in the Acer Care Center and then booting into linux worked for me as well. But at some time, it just stopped charging even when it was below 80%. This was actually really annoying since windows wanted to update and did not boot because my battery was below 25%, but I also couldn't charge it. So this method can actually be sort of "dangerous".
Another reason that getting it to work in TLP would be nice.

[dxvsh]

@Bartvelp That sounds rough. Sorry if I landed you in some trouble! In my case though, I've had this setting turned on for about a week now and its been working fine between linux and windows so far. There could be so many variations between your setup and mine that its hard to pinpoint what could be causing this strange behavior [eg: might be a different (bios/kernel/windows version/some other setting?)].

But you're totally right, it'd be much safer and cleaner to have this working in tlp. Someday, I hope!

[balthier82]

Hi guys, I have an Acer Nitro 5. I would really need the plugin for this laptop. I hope someone can figure out how to do this.

[linrunner]

Please save your declarations of wanting to have. They do nothing at all here in the issue. One of you Acer owners has to go and program a corresponding extension of the kernel driver. Writing the plugin is then trivial.

[frederik-h]

Please save your declarations of wanting to have. They do nothing at all here in the issue. One of you Acer owners has to go and program a corresponding extension of the kernel driver. Writing the plugin is then trivial.

I have implemented an experimental kernel driver for Acer's WMI battery control interface. So far I have only tested it on a Swift 3, but I would expect that Acer uses the same interface on other laptops as well. If you give it a try, please let me know if it works on your system.

[linrunner]

@frederik-h Great. It's nice when the light appears at the end of the tunnel. I suggest you include a note in your driver documentation about the percentage where charging stops when health mode is active. I will need the value for the TLP docs as well.

Are you planning to submit the driver for the mainline kernel?

[frederik-h]

@frederik-h Great. It's nice when the light appears at the end of the tunnel. I suggest you include a note in your driver documentation about the percentage where charging stops when health mode is active. I will need the value for the TLP docs as well.

I will add it. It stops at 79% on my system. I could not find any methods to modify this threshold. From the Acer Care Center screenshots and documentation that I have seen, I assume that the threshold is fixed. I have no Windows installation to verify the actual settings that are available in the Care Center.

Are you planning to submit the driver for the mainline kernel?

Yes, but it would be great to test it on some more systems beforehand. I am also a bit unsure if it wouldn't be better to offer the settings separately for all batteries found in the system. The WMI methods take the battery index as an argument, but all invocations of this method that I could find in the Care Center binaries seemed to call it for the first battery only. Hence, I decided to implement it like this as well.

[Bartvelp]

Yes, but it would be great to test it on some more systems beforehand.

Just tested it out on a Acer Aspire 5 A515-45G-R5A1, works like a charm.

I will add it. It stops at 79% on my system. I could not find any methods to modify this threshold. From the Acer Care Center screenshots and documentation that I have seen, I assume that the threshold is fixed. I have no Windows installation to verify the actual settings that are available in the Care Center.

Stops at 79% for me as well. I do have a windows install and can confirm the battery care toggle is modified when toggling using your kernel driver. There is no way to modify the threshold in Acer Care Center, as you already mentioned.

Thanks for your work @frederik-h , I am interested as to how you reverse engineered the care center, any plans on disclosing that?

[linrunner]

OK. I assume the charge threshold is 80% and the 79% is due to rounding.

Edit: confirmed by this Acer support article.