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 Could you please kindly give some suggestions about how to fix these warnings? Thanks, Jisheng > > vim +/ou_volt_max +666 drivers/base/power/opp/core.c > > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 650 if > (freq < old_freq) { > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 651 > ret = _set_opp_voltage(dev, reg, u_volt, u_volt_min, > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 652 > u_volt_max); > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 653 > if (ret) > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 654 > goto restore_freq; > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 655 } > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 656 > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 657 return > 0; > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 658 > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 659 > restore_freq: > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 660 if > (clk_set_rate(clk, old_freq)) > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 661 > dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n", > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 662 > __func__, old_freq); > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 663 > restore_voltage: > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 664 /* This > shouldn't harm even if the voltages weren't updated earlier */ > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 665 if > (!IS_ERR(old_opp)) > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 @666 > _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max); > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 667 > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 668 return > ret; > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 669 } > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 670 > EXPORT_SYMBOL_GPL(dev_pm_opp_set_rate); > 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 671 > 2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16 672 /* > OPP-dev Helpers */ > 2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16 673 static > void _kfree_opp_dev_rcu(struct rcu_head *head) > 06441658 drivers/base/power/opp.c Viresh Kumar 2015-07-29 674 { > > :::::: The code at line 666 was first introduced by commit > :::::: 6a0712f6f199e737aa5913d28ec4bd3a25de9660 PM / OPP: Add > dev_pm_opp_set_rate() > > :::::: TO: Viresh Kumar <viresh.ku...@linaro.org> > :::::: CC: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation
