Re: [PATCH] Input: bcm5974.c initialize raw_w, raw_x and raw_y before it get used
From: Jaswinder Singh Rajput <jaswinder@kernel.org>
Date: 2009-09-13 08:32:10
On Sun, 2009-09-13 at 01:24 +0200, Henrik Rydberg wrote:
Jaswinder Singh Rajput wrote:quoted
raw_w, raw_x and raw_y is used uninitialized for !raw_nThanks for the heads up, but actually not, since !raw_n also implies !(ptest > PRESSURE_LOW).
Then can we move 'if (ptest > PRESSURE_LOW && origin)' stuff to 'if (raw_n)'. If not then my patch is correct.
quoted
This also fixed these compilation warnings : CC [M] drivers/input/mouse/bcm5974.o drivers/input/mouse/bcm5974.c: In function ‘report_tp_state’: drivers/input/mouse/bcm5974.c:319: warning: ‘raw_y’ may be used uninitialized in this function drivers/input/mouse/bcm5974.c:319: warning: ‘raw_x’ may be used uninitialized in this function drivers/input/mouse/bcm5974.c:319: warning: ‘raw_w’ may be used uninitialized in this function Signed-off-by: Jaswinder Singh Rajput <redacted> --- drivers/input/mouse/bcm5974.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c index 2d8fc0b..171f345 100644 --- a/drivers/input/mouse/bcm5974.c +++ b/drivers/input/mouse/bcm5974.c@@ -345,7 +345,8 @@ static int report_tp_state(struct bcm5974 *dev, int size) /* set the integrated button if applicable */ if (c->tp_type == TYPE2) ibt = raw2int(dev->tp_data[BUTTON_TYPE2]); - } + } else + raw_w = raw_x = raw_y = 0; /* while tracking finger still valid, count all fingers */ if (ptest > PRESSURE_LOW && origin) {I would prefer treating raw_p on the same footing here, completing the set of non-obviously initialized variables. It might also make sense to utilize the same initialization technique already used in the code, thus:
No, then you are wasting cpu cycles and doing double initialization for some cases.
quoted hunk ↗ jump to hunk
diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c index 2d8fc0b..2f85876 100644 --- a/drivers/input/mouse/bcm5974.c +++ b/drivers/input/mouse/bcm5974.c@@ -316,7 +316,7 @@ static int report_tp_state(struct bcm5974 *dev, int size) const struct bcm5974_config *c = &dev->cfg; const struct tp_finger *f; struct input_dev *input = dev->input; - int raw_p, raw_w, raw_x, raw_y, raw_n; + int raw_p = 0, raw_w = 0, raw_x = 0, raw_y = 0, raw_n; int ptest = 0, origin = 0, ibt = 0, nmin = 0, nmax = 0; int abs_p = 0, abs_w = 0, abs_x = 0, abs_y = 0;I wonder how many cpu cycles in the world are spent making compilers happy.
It is not compiler mistake it is programming/logic mistakes. We should be thankful to compiler to pointing mistakes made by us. Thanks, -- JSR -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html