Hello, On Wed, Jun 22, 2011 at 03:25:03PM +0100, Richard Hughes wrote: > Hi, if this isn't the correct mailing list please yell. I'm the author > of upower which is a userspace service that presents the power devices > in the system as a DBus interface for the session to use. > > In struct power_supply there is a boolean use_for_apm which seems to > be 1 for devices actually powering the system, and 0 for devices > attached to the machine. Would this be sane to export into sysfs as > something sane? Nope, use_for_apm is a legacy stuff. It just says which battery should be reported via /proc/apm interface (if arch supports it). It should be removed completely someday. > The reason I ask, is that upower has to decide if the system as a > whole has several high level states, e.g. "low-power" or > "critically-low-power" and for that it needs to decide if the battery > backing the power supply device is critical to the system power state. > This would mean that a ACPI battery or UPS running low would mean the > system is low, but a USB mouse or a wacom tablet would not prompt the > low power warning. > > This email has been triggered by a bug report : > https://bugs.freedesktop.org/show_bug.cgi?id=38569 in which the kernel > patch http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=59d2334ac9f4255f5f8f3e4e1bf41653e0bba99e;hp=4da361b69102cdffe73006771eae7504d2cb8736 > added the power_supply device which confuses upower. > > The alternative is to change the wacom power_supply code from > type=POWER_SUPPLY_TYPE_BATTERY to something else, e.g. > POWER_SUPPLY_TYPE_ACCESSORY which upower can easily key from. I really > don't want to blacklist "battery_wacom" as that seems like such a > hack. Yeah, that seems sane. But I'm not sure if that should be a type thing. Instead, we might want to introduce additional 'struct device **supplied_to_devs' field in the 'struct power_supply' (we have supplied_to field, but it won't work as it holds only device names). So, the logic should be: bool power_supply_is_system_supply(device) { for_each_supplied_to(device, supplied_to) { if (!is_power_supply(supplied_to) return false; return power_supply_is_system_supply(supplied_to) } return true; } And the kernel might export 'system_supply' property for each battery. Wacom driver will need just a small modification: it should fill supplied_to_devs with its struct device. Plus, someday we might want to expose 'supplied_to' via sysfs directory. E.g., if supplied_to_devs == NULL, then /sys/power_supply/BAT/supplied_to/ symlinks to /sys/devices. I.e. it's a system battery/mains. If psy->supplied_to_devs == { dev1, dev2 }, then supplied_to/ contains symlinks to only these devices. Typical system with a removable battery (both AC0 and BAT0 power the whole system): AC0/supplied_to -> /sys/devices BAT0/supplied_to -> /sys/devices battery_wacom/supplied_to -> /sys/devices/pci0000\:00/0000\:00\:1c.0/wacom_input_device Typical system with a electrically non-removable battery, i.e. AC0 only powers BAT0, which powers a system: AC0/supplied_to -> /sys/devices/platform/BAT0 BAT0/supplied_to -> /sys/devices battery_wacom/supplied_to -> /sys/devices/pci0000\:00/0000\:00\:1c.0/wacom_input_device -- Anton Vorontsov Email: cbouatmailru@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
