Messages in this thread | | | Date | Mon, 25 Jul 2016 14:05:11 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit |
| |
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? >
| |