From: Jisheng Zhang <jszhang@marvell.com>
To: kbuild test robot <lkp@intel.com>,
vireshk@kernel.org, nm@ti.com, sboyd@codeaurora.org,
rjw@rjwysocki.net, gregkh@linuxfoundation.org,
Arnd Bergmann <arnd@arndb.de>
Cc: kbuild-all@01.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit
Date: Mon, 25 Jul 2016 14:05:11 +0800 [thread overview]
Message-ID: <20160725140511.1639552d@xhacker> (raw)
In-Reply-To: <20160725131947.644e6166@xhacker>
On Mon, 25 Jul 2016 13:19:47 +0800 Jisheng Zhang wrote:
> Dear all,
>
> On Fri, 22 Jul 2016 22:30:53 +0800 kbuild test robot wrote:
>
> > Hi,
> >
> > [auto build test WARNING on pm/linux-next]
> > [also build test WARNING on v4.7-rc7 next-20160722]
> > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> >
> > url: https://github.com/0day-ci/linux/commits/Jisheng-Zhang/PM-OPP-optimize-dev_pm_opp_set_rate-a-bit/20160722-205339
> > base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
> > config: x86_64-allmodconfig (attached as .config)
> > compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
> > reproduce:
> > # save the attached .config to linux build tree
> > make ARCH=x86_64
> >
> > Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
> > http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
> >
> > All warnings (new ones prefixed by >>):
> >
> > drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_max' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_min' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt' may be used uninitialized in this function [-Wmaybe-uninitialized]
>
> These warnings seem weired. We only use them when !IS_ERR(old_opp), and we
> should already set them if !IS_ERR(old_opp). Another weired thing is if
> we add something, printk e.g in _find_freq_ceil(), then these warnings disappear
Hmm, it looks that gcc will inline _find_freq_ceil(), then gcc can't
detect that ou_volt* are already set. Mark _find_freq_ceil() noinline would fix
the warnings
Thanks,
Jisheng
>
> Could you please kindly give some suggestions about how to fix these warnings?
>
next prev parent reply other threads:[~2016-07-25 6:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-22 12:42 [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit Jisheng Zhang
2016-07-22 14:30 ` kbuild test robot
2016-07-25 5:19 ` Jisheng Zhang
2016-07-25 6:05 ` Jisheng Zhang [this message]
2016-07-22 16:21 ` Viresh Kumar
2016-07-25 5:12 ` Jisheng Zhang
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