Date: Mon, 6 Mar 2023 00:39:30 -0600 From: Kyle Evans <kevans@freebsd.org> To: Warner Losh <imp@bsdimp.com> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: acpi_cmbat with charge-limited battery Message-ID: <CACNAnaHHUoxBpoyynUXtLWnghLTV9S5CNjSiURb%2BDiJDF7WjFw@mail.gmail.com> In-Reply-To: <CANCZdfp4JZCsuaQhbSuMYrYseu5n%2BHmASdEiCb0QM-2hr5Ja4g@mail.gmail.com> References: <CACNAnaG=vk0jnk4zhvmuW7cRTMFdCuiMJp7mBOMx_rKy7umuoQ@mail.gmail.com> <CANCZdfp4JZCsuaQhbSuMYrYseu5n%2BHmASdEiCb0QM-2hr5Ja4g@mail.gmail.com>
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On Sun, Mar 5, 2023 at 9:33=E2=80=AFPM Warner Losh <imp@bsdimp.com> wrote: > > > > On Sun, Mar 5, 2023 at 7:20=E2=80=AFPM Kyle Evans <kevans@freebsd.org> wr= ote: >> >> 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... > The more I think about it (and with your generally confirmatory response), the more I think approaching both problems independently is probably good. I added a quick sysctl to acpi_cmbat to allow an interval for folks with broken firmware like myself; I'll probably throw that up for review tomorrow-ish. I'll also reach out to frame.work folks and see if they can improve this in some way, but I suspect any action there will take a while. Thanks, Kyle Evans
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