ACPI / battery: Deal better with neither design nor full capacity not being reported
authorHans de Goede <hdegoede@redhat.com>
Tue, 10 Dec 2019 09:57:52 +0000 (10:57 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 11 Feb 2020 12:33:59 +0000 (04:33 -0800)
commit70435409cee45e60d70dbb961c0d88f88bfbb10d
tree2ea3bb5259f17962413487ca7f6e8060e74523ee
parenta20180e04c26b676224793c95f6e6f796ec34169
ACPI / battery: Deal better with neither design nor full capacity not being reported

commit ff3154d1d89a2343fd5f82e65bc0cf1d4e6659b3 upstream.

Commit b41901a2cf06 ("ACPI / battery: Do not export energy_full[_design] on
devices without full_charge_capacity") added support for some (broken)
devices which always report 0 for both design_capacity and
full_charge_capacity.

Since the device that commit was written as a fix for is not reporting any
form of "full" capacity we cannot calculate the value for the
POWER_SUPPLY_PROP_CAPACITY, this is worked around by using an alternative
array of available properties which does not contain this property.

This is necessary because userspace (upower) treats us returning -ENODEV
as 0 and then typically will trigger an emergency shutdown because of that.
Userspace does not do this if the capacity sysfs attribute is not present
at all.

There are two potential problems with that commit:
 1) It assumes that both full_charge- and design-capacity are broken at the
    same time and only checks if full_charge- is broken.
 2) It assumes that this only ever happens for devices which report energy
    units rather then charge units.

This commit fixes both issues by only using the alternative
array of available properties if both full_charge- and design-capacity are
broken and by also adding an alternative array of available properties for
devices using mA units.

Fixes: b41901a2cf06 ("ACPI / battery: Do not export energy_full[_design] on devices without full_charge_capacity")
Cc: 4.19+ <stable@vger.kernel.org> # 4.19+
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/acpi/battery.c