From: Chen Gang <gang.chen.5i5j@gmail.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: floe@butterbrot.org, rydberg@euromail.se,
David Herrmann <dh.herrmann@gmail.com>,
rkuo <rkuo@codeaurora.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-input@vger.kernel.org
Subject: Re: [PATCH] drivers: input: touchscreen: sur40: use static variable instead of stack varialbe for 'packet_id'
Date: Thu, 28 Nov 2013 12:24:28 +0800 [thread overview]
Message-ID: <5296C57C.3010900@gmail.com> (raw)
In-Reply-To: <20131128040741.GD15452@core.coreip.homeip.net>
On 11/28/2013 12:07 PM, Dmitry Torokhov wrote:
> 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().
OK, thanks, I will/should send patch v2 for it.
--
Chen Gang
next prev parent reply other threads:[~2013-11-28 4:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-19 3:10 [PATCH] arch: hexagon: kernel: add export symbol function __delay() Chen Gang
2013-11-25 1:19 ` rkuo
2013-11-25 1:50 ` Chen Gang
2013-11-27 2:15 ` [PATCH] drivers: input: touchscreen: sur40: use static variable instead of stack varialbe for 'packet_id' Chen Gang
2013-11-28 4:07 ` Dmitry Torokhov
2013-11-28 4:24 ` Chen Gang [this message]
2013-11-28 4:34 ` [PATCH v2] drivers: input: touchscreen: sur40: remove stack variable 'packet_id' from sur40_poll() Chen Gang
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