On Tue, May 01, 2012 at 02:14:08PM -0500, Jonathan Nieder wrote: > (cc-ing Andy) > Adrian Fita wrote: > > > Also, searching on Google after "upowerd device > > removed:/org/freedesktop/UPower/devices/battery_BAT0", reveals much > > more bug reports with the exact issue. > > Thanks. That confirms the high CPU consumption in upowerd --- > see [1], for example. > > [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/987807 It does seem somewhat heavyweight to be removing and reinstalling all of the sysfs files every time we get one of these events. I am assuming here that some BIOSs are using this interface to tell us the batery capacity has changed and triggering the constant add/remove of the devices and associated flickering. >From the description of the change this is necessary because the capacity units may change over time? Can we not use those to avoid this update? I presume it is these two we are referring to? int capacity_granularity_1; int capacity_granularity_2; If those are unchanged perhaps we can just skip the update? Something like the below (completly untested, for discussion). Thoughts? -apw commit d558d0c38e26e2c7eae68d19f4d2fa3ecd8e31f2 Author: Andy Whitcroft <apw@xxxxxxxxxxxxx> Date: Thu May 3 09:52:28 2012 +0100 battery: only refresh the sysfs files when pertinant information changes We only need to regenerate the sysfs files when the capacity units change, avoid the update otherwise. Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxxx> diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index eb18c44..f8d37b4 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -643,10 +643,20 @@ static int acpi_battery_update(struct acpi_battery *battery) static void acpi_battery_refresh(struct acpi_battery *battery) { + int cg1, cg2; + if (!battery->bat.dev) return; + cg1 = battery->capacity_granularity_1; + cg2 = battery->capacity_granularity_2; + acpi_battery_get_info(battery); + + if (cg1 == battery->capacity_granularity_1 && + cg2 == capacity_granularity_2) + return; + /* The battery may have changed its reporting units. */ sysfs_remove_battery(battery); sysfs_add_battery(battery); _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
