| Message ID | 1537255520-41614-1-git-send-email-zhongjiang@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: sun4i: Fix a uninitialized variable warning. | expand |
On Tue, Sep 18, 2018 at 03:25:20PM +0800, zhong jiang wrote: > Fix the following compile warning: > > drivers/gpu/drm/sun4i/sun4i_tcon.c:1088: warning: 'has_lvds_alt' may be used uninitialized in this function [-Wmaybe-uninitialized] > bool has_lvds_rst, has_lvds_alt, can_lvds; > > Signed-off-by: zhong jiang <zhongjiang@huawei.com> I can't see any code path that would lead to an uninitialized usage of that variable. Which compiler produced that warning? I tried building it today with gcc 8.1.1, and I don't see that warning either. Maxime
On 2018/9/19 16:47, Maxime Ripard wrote: > On Tue, Sep 18, 2018 at 03:25:20PM +0800, zhong jiang wrote: >> Fix the following compile warning: >> >> drivers/gpu/drm/sun4i/sun4i_tcon.c:1088: warning: 'has_lvds_alt' may be used uninitialized in this function [-Wmaybe-uninitialized] >> bool has_lvds_rst, has_lvds_alt, can_lvds; >> >> Signed-off-by: zhong jiang <zhongjiang@huawei.com> > I can't see any code path that would lead to an uninitialized usage of > that variable. > > Which compiler produced that warning? I tried building it today with > gcc 8.1.1, and I don't see that warning either. > > Maxime > I indeed hit the issue. the gcc version is gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609 Thanks, zhong jiang
On Wed, Sep 19, 2018 at 05:01:32PM +0800, zhong jiang wrote: > On 2018/9/19 16:47, Maxime Ripard wrote: > > On Tue, Sep 18, 2018 at 03:25:20PM +0800, zhong jiang wrote: > >> Fix the following compile warning: > >> > >> drivers/gpu/drm/sun4i/sun4i_tcon.c:1088: warning: 'has_lvds_alt' may be used uninitialized in this function [-Wmaybe-uninitialized] > >> bool has_lvds_rst, has_lvds_alt, can_lvds; > >> > >> Signed-off-by: zhong jiang <zhongjiang@huawei.com> > > I can't see any code path that would lead to an uninitialized usage of > > that variable. > > > > Which compiler produced that warning? I tried building it today with > > gcc 8.1.1, and I don't see that warning either. > > I indeed hit the issue. the gcc version is > gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609 I've tested with 4.* gcc, and it didn't report any error. It seems to be a false positive for this particular version, so there's no need to merge that patch. If more people are affected, we'll obviously do something about it though. Thanks! Maxime
On 2018/9/21 22:26, Maxime Ripard wrote: > On Wed, Sep 19, 2018 at 05:01:32PM +0800, zhong jiang wrote: >> On 2018/9/19 16:47, Maxime Ripard wrote: >>> On Tue, Sep 18, 2018 at 03:25:20PM +0800, zhong jiang wrote: >>>> Fix the following compile warning: >>>> >>>> drivers/gpu/drm/sun4i/sun4i_tcon.c:1088: warning: 'has_lvds_alt' may be used uninitialized in this function [-Wmaybe-uninitialized] >>>> bool has_lvds_rst, has_lvds_alt, can_lvds; >>>> >>>> Signed-off-by: zhong jiang <zhongjiang@huawei.com> >>> I can't see any code path that would lead to an uninitialized usage of >>> that variable. >>> >>> Which compiler produced that warning? I tried building it today with >>> gcc 8.1.1, and I don't see that warning either. >> I indeed hit the issue. the gcc version is >> gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609 > I've tested with 4.* gcc, and it didn't report any error. It seems to > be a false positive for this particular version, so there's no need to > merge that patch. If more people are affected, we'll obviously do > something about it though. Yep, it rarely occur. I just happen once. Thank you for reply. Sincerely, zhong jiang > Thanks! > Maxime >
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index c78cd35..563cc8f 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -1086,7 +1086,7 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master, struct device_node *remote; struct sun4i_tcon *tcon; struct reset_control *edp_rstc; - bool has_lvds_rst, has_lvds_alt, can_lvds; + bool has_lvds_rst, has_lvds_alt = false, can_lvds; int ret; engine = sun4i_tcon_find_engine(drv, dev->of_node);
Fix the following compile warning: drivers/gpu/drm/sun4i/sun4i_tcon.c:1088: warning: 'has_lvds_alt' may be used uninitialized in this function [-Wmaybe-uninitialized] bool has_lvds_rst, has_lvds_alt, can_lvds; Signed-off-by: zhong jiang <zhongjiang@huawei.com> --- drivers/gpu/drm/sun4i/sun4i_tcon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)