Messages in this thread | | | Date | Wed, 27 Nov 2013 20:07:41 -0800 | From | Dmitry Torokhov <> | Subject | Re: [PATCH] drivers: input: touchscreen: sur40: use static variable instead of stack varialbe for 'packet_id' |
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Hi Chen,
On Wed, Nov 27, 2013 at 10:15:33AM +0800, Chen Gang wrote: > 'packet_id' is used for checking sequence whether in order, it need be > static variable independent from sur40_poll(). > > The related warning (with allmodconfig under hexagon): > > drivers/input/touchscreen/sur40.c: In function 'sur40_poll': > drivers/input/touchscreen/sur40.c:297:6: warning: 'packet_id' may be used uninitialized in this function [-Wuninitialized] > > > Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> > --- > drivers/input/touchscreen/sur40.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c > index cfd1b7e..5dfd01a 100644 > --- a/drivers/input/touchscreen/sur40.c > +++ b/drivers/input/touchscreen/sur40.c > @@ -251,7 +251,7 @@ static void sur40_poll(struct input_polled_dev *polldev) > struct sur40_state *sur40 = polldev->private; > struct input_dev *input = polldev->input; > int result, bulk_read, need_blobs, packet_blobs, i; > - u32 packet_id; > + static u32 packet_id;
It is usually not a good idea to use statics in device drivers as it does not work well when you have several devices of the same type present in a system. Also, we process all blobs in one pass so there is no need to preserve value of packet_id between calls to sur40_poll().
Thanks.
-- Dmitry
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