Hi Jae, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on wsa/i2c/for-next] [also build test WARNING on v4.19 next-20181029] [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/Jae-Hyun-Yoo/i2c-aspeed-Add-bus-idle-waiting-logic-for-multi-master-use-cases/20181030-051719 base: https://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/for-next config: xtensa-allyesconfig (attached as .config) compiler: xtensa-linux-gcc (GCC) 8.1.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree GCC_VERSION=8.1.0 make.cross ARCH=xtensa 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 >>): In file included from include/linux/ktime.h:25, from include/linux/rcutiny.h:28, from include/linux/rcupdate.h:209, from include/linux/srcu.h:33, from include/linux/notifier.h:16, from include/linux/clk.h:17, from drivers/i2c/busses/i2c-aspeed.c:13: drivers/i2c/busses/i2c-aspeed.c: In function 'aspeed_i2c_master_xfer': >> include/linux/jiffies.h:108:15: warning: 'check_started' may be used uninitialized in this function [-Wmaybe-uninitialized] ((long)((b) - (a)) < 0)) ^ drivers/i2c/busses/i2c-aspeed.c:607:16: note: 'check_started' was declared here unsigned long check_started; ^~~~~~~~~~~~~ -- In file included from include/linux/ktime.h:25, from include/linux/rcutiny.h:28, from include/linux/rcupdate.h:209, from include/linux/srcu.h:33, from include/linux/notifier.h:16, from include/linux/clk.h:17, from drivers/i2c//busses/i2c-aspeed.c:13: drivers/i2c//busses/i2c-aspeed.c: In function 'aspeed_i2c_master_xfer': >> include/linux/jiffies.h:108:15: warning: 'check_started' may be used uninitialized in this function [-Wmaybe-uninitialized] ((long)((b) - (a)) < 0)) ^ drivers/i2c//busses/i2c-aspeed.c:607:16: note: 'check_started' was declared here unsigned long check_started; ^~~~~~~~~~~~~ vim +/check_started +108 include/linux/jiffies.h ^1da177e Linus Torvalds 2005-04-16 91 ^1da177e Linus Torvalds 2005-04-16 92 /* ^1da177e Linus Torvalds 2005-04-16 93 * These inlines deal with timer wrapping correctly. You are ^1da177e Linus Torvalds 2005-04-16 94 * strongly encouraged to use them ^1da177e Linus Torvalds 2005-04-16 95 * 1. Because people otherwise forget ^1da177e Linus Torvalds 2005-04-16 96 * 2. Because if the timer wrap changes in future you won't have to ^1da177e Linus Torvalds 2005-04-16 97 * alter your driver code. ^1da177e Linus Torvalds 2005-04-16 98 * ^1da177e Linus Torvalds 2005-04-16 99 * time_after(a,b) returns true if the time a is after time b. ^1da177e Linus Torvalds 2005-04-16 100 * ^1da177e Linus Torvalds 2005-04-16 101 * Do this with "<0" and ">=0" to only test the sign of the result. A ^1da177e Linus Torvalds 2005-04-16 102 * good compiler would generate better code (and a really good compiler ^1da177e Linus Torvalds 2005-04-16 103 * wouldn't care). Gcc is currently neither. ^1da177e Linus Torvalds 2005-04-16 104 */ ^1da177e Linus Torvalds 2005-04-16 105 #define time_after(a,b) \ ^1da177e Linus Torvalds 2005-04-16 106 (typecheck(unsigned long, a) && \ ^1da177e Linus Torvalds 2005-04-16 107 typecheck(unsigned long, b) && \ 5a581b36 Paul E. McKenney 2013-07-27 @108 ((long)((b) - (a)) < 0)) ^1da177e Linus Torvalds 2005-04-16 109 #define time_before(a,b) time_after(b,a) ^1da177e Linus Torvalds 2005-04-16 110 :::::: The code at line 108 was first introduced by commit :::::: 5a581b367b5df0531265311fc681c2abd377e5e6 jiffies: Avoid undefined behavior from signed overflow :::::: TO: Paul E. McKenney :::::: CC: Paul E. McKenney --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation