acpi_cmbat with charge-limited battery
- Reply: Warner Losh : "Re: acpi_cmbat with charge-limited battery"
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Date: Mon, 06 Mar 2023 02:19:56 UTC
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. Thanks, Kyle Evans