tree: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git pci/aspm head: c79aafccbc64ed34ec6dce84cfa111e839044058 commit: c79aafccbc64ed34ec6dce84cfa111e839044058 [1/1] PCI/ASPM: Move LTR, ASPM L1SS restore closer to use config: xtensa-virt_defconfig (attached as .config) compiler: xtensa-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/commit/?i... git remote add pci https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git git fetch --no-tags pci pci/aspm git checkout c79aafccbc64ed34ec6dce84cfa111e839044058 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=xtensa If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): drivers/pci/pci.c: In function 'pci_restore_pcie_state': drivers/pci/pci.c:1450:2: error: implicit declaration of function 'pci_restore_ltr_state'; did you mean 'pci_restore_ptm_state'? [-Werror=implicit-function-declaration] 1450 | pci_restore_ltr_state(dev); /* LTR enabled in DEVCTL2 */ | ^~~~~~~~~~~~~~~~~~~~~ | pci_restore_ptm_state drivers/pci/pci.c: At top level: 1523 | static void pci_restore_ltr_state(struct pci_dev *dev) | ^~~~~~~~~~~~~~~~~~~~~ drivers/pci/pci.c:1523:13: error: static declaration of 'pci_restore_ltr_state' follows non-static declaration drivers/pci/pci.c:1450:2: note: previous implicit declaration of 'pci_restore_ltr_state' was here 1450 | pci_restore_ltr_state(dev); /* LTR enabled in DEVCTL2 */ | ^~~~~~~~~~~~~~~~~~~~~ drivers/pci/pci.c:1523:13: warning: 'pci_restore_ltr_state' defined but not used [-Wunused-function] 1523 | static void pci_restore_ltr_state(struct pci_dev *dev) | ^~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +/pci_restore_ltr_state +1523 drivers/pci/pci.c dbbfadf2319005 Bjorn Helgaas 2019-01-09 1522 dbbfadf2319005 Bjorn Helgaas 2019-01-09 @1523 static void pci_restore_ltr_state(struct pci_dev *dev) dbbfadf2319005 Bjorn Helgaas 2019-01-09 1524 { dbbfadf2319005 Bjorn Helgaas 2019-01-09 1525 struct pci_cap_saved_state *save_state; dbbfadf2319005 Bjorn Helgaas 2019-01-09 1526 int ltr; dbbfadf2319005 Bjorn Helgaas 2019-01-09 1527 u16 *cap; dbbfadf2319005 Bjorn Helgaas 2019-01-09 1528 dbbfadf2319005 Bjorn Helgaas 2019-01-09 1529 save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR); dbbfadf2319005 Bjorn Helgaas 2019-01-09 1530 ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR); dbbfadf2319005 Bjorn Helgaas 2019-01-09 1531 if (!save_state || !ltr) dbbfadf2319005 Bjorn Helgaas 2019-01-09 1532 return; dbbfadf2319005 Bjorn Helgaas 2019-01-09 1533 dbbfadf2319005 Bjorn Helgaas 2019-01-09 1534 cap = (u16 *)&save_state->cap.data[0]; dbbfadf2319005 Bjorn Helgaas 2019-01-09 1535 pci_write_config_word(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, *cap++); dbbfadf2319005 Bjorn Helgaas 2019-01-09 1536 pci_write_config_word(dev, ltr + PCI_LTR_MAX_NOSNOOP_LAT, *cap++); dbbfadf2319005 Bjorn Helgaas 2019-01-09 1537 } cc692a5f1e9816 Stephen Hemminger 2006-11-08 1538 :::::: The code at line 1523 was first introduced by commit :::::: dbbfadf2319005cf528b0f15f12a05d4e4644303 PCI/ASPM: Save LTR Capability for suspend/resume :::::: TO: Bjorn Helgaas <bhelgaas(a)google.com&gt; :::::: CC: Bjorn Helgaas <helgaas(a)kernel.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org