diff options
| author | Daniel Mack <daniel@caiaq.de> | 2009-03-12 14:31:30 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-12 16:20:23 -0700 |
| commit | a4e3f91b98d86ae0b5c816fe45190bb29ac32f71 (patch) | |
| tree | a7a24399163031587cd63ea24112a90d9cc3e84e /drivers/power | |
| parent | a3cfbb53b1764a3d1f58ddc032737ab9edaa7d41 (diff) | |
| download | lwn-a4e3f91b98d86ae0b5c816fe45190bb29ac32f71.tar.gz lwn-a4e3f91b98d86ae0b5c816fe45190bb29ac32f71.zip | |
ds2760_battery.c: fix division by zero
The 'battery remaining capacity' calculation in
drivers/power/ds2760_battery.c lacks a parameter check to a division
operation which causes the kernel to oops on my board.
[ 21.233750] Division by zero in kernel.
[ 21.237646] [<c002955c>] (__div0+0x0/0x20) from [<c012561c>] (Ldiv0+0x8/0x10)
[ 21.244816] [<c01bef34>] (ds2760_battery_read_status+0x0/0x2a4) from [<c01bf3a4>] (ds2760_battery_get_property+0x30/0xdc)
[ 21.255803] r8:c03a22c0 r7:c7886100 r6:00000009 r5:c782fe7c r4:c7886084
[ 21.262518] [<c01bf374>] (ds2760_battery_get_property+0x0/0xdc) from [<c01bde98>] (power_supply_show_property+0x48/0x114)
[ 21.273480] r6:c7996000 r5:00000009 r4:00000000
[ 21.278111] [<c01bde50>] (power_supply_show_property+0x0/0x114) from [<c01be158>] (power_supply_uevent+0x188/0x280)
[ 21.288537] r8:00000001 r7:c7886100 r6:c7996000 r5:000000b4 r4:00000000
[ 21.295222] [<c01bdfd0>] (power_supply_uevent+0x0/0x280) from [<c015c664>] (dev_uevent+0xd4/0x10c)
[ 21.304199] [<c015c590>] (dev_uevent+0x0/0x10c) from [<c0128440>] (kobject_uevent_env+0x180/0x390)
[ 21.313170] r5:00000000 r4:c78860ac
[ 21.316725] [<c01282c0>] (kobject_uevent_env+0x0/0x390) from [<c0128664>] (kobject_uevent+0x14/0x18)
[ 21.325850] [<c0128650>] (kobject_uevent+0x0/0x18) from [<c01bdc34>] (power_supply_changed_work+0x5c/0x70)
[ 21.335506] [<c01bdbd8>] (power_supply_changed_work+0x0/0x70) from [<c004d290>] (run_workqueue+0xbc/0x144)
[ 21.345167] r4:c7812040
[ 21.347716] [<c004d1d4>] (run_workqueue+0x0/0x144) from [<c004d94c>] (worker_thread+0xa8/0xbc)
[ 21.356296] r7:c7812040 r6:c7820b00 r5:c782ffa4 r4:c7812048
[ 21.361957] [<c004d8a4>] (worker_thread+0x0/0xbc) from [<c0051008>] (kthread+0x5c/0x94)
[ 21.369971] r7:00000000 r6:c004d8a4 r5:c7812040 r4:c782e000
[ 21.375612] [<c0050fac>] (kthread+0x0/0x94) from [<c00403d0>] (do_exit+0x0/0x688)
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
Acked-by: Matt Reimer <mreimer@vpop.net>
Acked-by: Anton Vorontsov <cbou@mail.ru>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/power')
| -rw-r--r-- | drivers/power/ds2760_battery.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/power/ds2760_battery.c b/drivers/power/ds2760_battery.c index 1d768928e0bb..a52d4a11652d 100644 --- a/drivers/power/ds2760_battery.c +++ b/drivers/power/ds2760_battery.c @@ -180,10 +180,13 @@ static int ds2760_battery_read_status(struct ds2760_device_info *di) di->empty_uAh = battery_interpolate(scale, di->temp_C / 10); di->empty_uAh *= 1000; /* convert to µAh */ - /* From Maxim Application Note 131: remaining capacity = - * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ - di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / - (di->full_active_uAh - di->empty_uAh); + if (di->full_active_uAh == di->empty_uAh) + di->rem_capacity = 0; + else + /* From Maxim Application Note 131: remaining capacity = + * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ + di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / + (di->full_active_uAh - di->empty_uAh); if (di->rem_capacity < 0) di->rem_capacity = 0; |