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Subject[PATCH] ACPI: battery: use cache_time as cache "enabled"
Date
From: Lucas Rangit Magasweran <lucas.magasweran@ieee.org>

When battery state is not cached the module parameter cache_time is 0
and battery->update_time starts at 0. However, it set to jiffies in
each call to acpi_battery_get_state() and should not be used to
determine if a cache time is used.

Using battery->update_time causes the evaluation of time_before()
even though cache_time is 0.

This is a minor issue as the behavior is still as expected.
Even if kernel HZ was very slow and jiffies remained equal, the
expected branch (false) would be taken because time_before() is
used instead of time_before_eq().

Signed-off-by: Lucas Rangit Magasweran <lucas.magasweran@ieee.org>
---
drivers/acpi/battery.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index d79ad84..f88bc9f 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -549,7 +549,7 @@ static int acpi_battery_get_state(struct acpi_battery *battery)
if (!acpi_battery_present(battery))
return 0;

- if (battery->update_time &&
+ if (cache_time &&
time_before(jiffies, battery->update_time +
msecs_to_jiffies(cache_time)))
return 0;
--
2.7.4
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