lkml.org 
[lkml]   [2018]   [Jul]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4] backlight: pwm_bl: Fix uninitialized variable
Date
Currently, if the DT does not define num-interpolated-steps then
num_steps is undefined and the interpolation code will deploy randomly.
Fix with a simple initialize to zero.

Fixes: 573fe6d1c25c ("backlight: pwm_bl: Linear interpolation between brightness-levels")
Reported-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
---

Notes:
v4:
- Remove line break from Fixes: and update the *-by:s

v3:
- Switch to the simplest fix and zero the uninitialized variable. git
grep indicates that ~25% of calls to of_property_read_u32() use this
pattern (pre-initialize optional properties with sane values and
ignore the return code).

v2:
- Simplify SoB chain (with Marcel's permission)
- Separate complex if statement and make other similar calls use same
return code checking approach
- Tidy up comment formatting and fix pre-existing grammar error

drivers/video/backlight/pwm_bl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 9ee4c1b735b2..bdfcc0a71db1 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -250,7 +250,7 @@ static int pwm_backlight_parse_dt(struct device *dev,
struct device_node *node = dev->of_node;
unsigned int num_levels = 0;
unsigned int levels_count;
- unsigned int num_steps;
+ unsigned int num_steps = 0;
struct property *prop;
unsigned int *table;
int length;
--
2.17.1
\
 
 \ /
  Last update: 2018-07-25 09:39    [W:0.157 / U:5.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site