Date: Mon, 6 Mar 2023 21:57:04 -0600 From: Kyle Evans <kevans@freebsd.org> To: "Rodney W. Grimes" <freebsd-rwg@gndrsh.dnsmgr.net> Cc: Kyle Evans <kevans@freebsd.org>, Warner Losh <imp@bsdimp.com>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: acpi_cmbat with charge-limited battery Message-ID: <CACNAnaHa%2BfQy9fuVsMXDvYnQ8%2BOHMVpVxpWhNA0y7aFA6Cu%2BBw@mail.gmail.com> In-Reply-To: <202303061449.326EnUrV078466@gndrsh.dnsmgr.net> References: <CACNAnaHHUoxBpoyynUXtLWnghLTV9S5CNjSiURb%2BDiJDF7WjFw@mail.gmail.com> <202303061449.326EnUrV078466@gndrsh.dnsmgr.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Mar 6, 2023 at 8:49 AM Rodney W. Grimes <freebsd-rwg@gndrsh.dnsmgr.net> wrote: > > > On Sun, Mar 5, 2023 at 9:33?PM Warner Losh <imp@bsdimp.com> wrote: > > > > > > > > > > > > On Sun, Mar 5, 2023 at 7:20?PM Kyle Evans <kevans@freebsd.org> wrote: > > >> > > >> Hello! > > >> > > >> I've dealt with this mainly over the weekend, but my solution was to > > >> just disable acpi_cmbat entirely, which is maybe not the best solution > > >> but I can't tell if this should be considered a firmware bug or if > > >> it's something we could find a way to workaround in the kernel. > > >> > > >> Basically, I've set the firmware on my frame.work laptop to limit the > > >> battery charge to 80%. When it hits 80% while plugged in, things get a > > >> little funky- I assume it's because the firmware's trying to carefully > > >> maintain the limit, but I end up getting (at least) one acpi > > >> notification per second, alternating between BST_CHANGE/BIX_CHANGE, > > >> which in turn drives up CPU usage as we tap it out to devd and upowerd > > >> picks it up. upowerd ends up pegging a core consistently. > > >> > > >> Should we be rate-limiting these devd notifications? Is this even > > >> reasonable behavior for the firmware? I'm not really sure how other OS > > >> behave here, but I haven't really seen any complaints from other > > >> framework'ers. > > > > > > > > > Seems like this is crappy firmware behavior and we should rate > > > limit in the driver... It's not useful information to be sharing once > > > a second... > > > > > I agree with that assesment of the firmware, but it brings up > a question of is the firmware actually doing just what it is > told? I see above an upper limit on the charge has been > set at 80%, but I do not see any mention of a "resume charging" > after the battery drops to XX%. I assume what is happening is > the charge stops at 80%, we drop some load on the battery and > it quickly drops to 79%, and the firmware decides it must > start to charge again. > > Kyle, does the bios have settings for a resume charging? > Also might be intereting to watch the battery level in > a tight loop to see if you can catch the drop. > I haven't found any such setting, even after my last update to a BIOS from ~a couple months ago. I tried `acpiconf -i0` in a tight loop and captured the below transition. Interestingly, I wasn't able to capture anywhere where it was charging and reported as < 80%, but for all I know that's a rounding error and there's just not enough tolerance to catch the difference. Design capacity: 3572 mAh Last full capacity: 3503 mAh Technology: secondary (rechargeable) Design voltage: 15400 mV Capacity (warn): 350 mAh Capacity (low): 105 mAh Cycle Count: 5 Measurement Accuracy: 0 % Max Sampling Time: 0 ms Min Sampling Time: 0 ms Max Average Interval: 0 ms Min Average Interval: 0 ms Low/warn granularity: 264 mAh Warn/full granularity: 3780 mAh Model number: Framewo Serial number: 0260 Type: LION OEM info: NVT State: discharging Remaining capacity: 80% Remaining time: 706:15 Present rate: 4 mA (66 mW) Present voltage: 16594 mV Design capacity: 3572 mAh Last full capacity: 3503 mAh Technology: secondary (rechargeable) Design voltage: 15400 mV Capacity (warn): 350 mAh Capacity (low): 105 mAh Cycle Count: 5 Measurement Accuracy: 0 % Max Sampling Time: 0 ms Min Sampling Time: 0 ms Max Average Interval: 0 ms Min Average Interval: 0 ms Low/warn granularity: 264 mAh Warn/full granularity: 3780 mAh Model number: Framewo Serial number: 0260 Type: LION OEM info: NVT State: charging Remaining capacity: 80% Remaining time: unknown Present rate: 4 mA (66 mW) Present voltage: 16600 mV
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CACNAnaHa%2BfQy9fuVsMXDvYnQ8%2BOHMVpVxpWhNA0y7aFA6Cu%2BBw>