From mboxrd@z Thu Jan 1 00:00:00 1970 From: zhong jiang Subject: Re: [PATCH] HID: logitech: fix a used uninitialized GCC warning Date: Thu, 13 Sep 2018 15:39:02 +0800 Message-ID: <5B9A1416.7010405@huawei.com> References: <1536810739-27342-1-git-send-email-zhongjiang@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Benjamin Tissoires Cc: Jiri Kosina , HID CORE LAYER , lkml List-Id: linux-input@vger.kernel.org On 2018/9/13 15:01, Benjamin Tissoires wrote: > On Thu, Sep 13, 2018 at 6:04 AM zhong jiang wrote: >> Fix the following compile warning: >> >> drivers/hid/hid-logitech-hidpp.c: In function ‘hi_res_scroll_enable’: >> drivers/hid/hid-logitech-hidpp.c:2714:54: warning: ‘multiplier’ may be used uninitialized in this function [-Wmaybe-uninitialized] >> hidpp->vertical_wheel_counter.resolution_multiplier = multiplier; >> >> Signed-off-by: zhong jiang >> --- >> drivers/hid/hid-logitech-hidpp.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c >> index 5f0c080..83c43dd 100644 >> --- a/drivers/hid/hid-logitech-hidpp.c >> +++ b/drivers/hid/hid-logitech-hidpp.c >> @@ -2696,7 +2696,7 @@ static int hi_res_scroll_look_up_microns(__u32 product_id) >> static int hi_res_scroll_enable(struct hidpp_device *hidpp) >> { >> int ret; >> - u8 multiplier; >> + u8 uninitialized_var(multiplier); > I think your patch is correct (multiplier will be set given the code > path), but IMO, it feels terribly wrong to explicitly remove this > warning this way. The problem is that if someone else adds a new piece > of code, we might miss the fact that multiplier is not set and we > might show garbage in the hid_info call. Make sense. > > Why don't you initialize the value to 8 as in the 'else' statement and > remove the now duplicated assignement in this else statement? Will do in v2. Thank you for your suggestion. Thanks, zhong jiang > Cheers, > Benjamin > >> if (hidpp->quirks & HIDPP_QUIRK_HI_RES_SCROLL_X2121) { >> ret = hidpp_hrw_set_wheel_mode(hidpp, false, true, false); >> -- >> 1.7.12.4 >> > . >