On 05/12/2011 04:32 PM, Jesse Barnes wrote: > On Wed, 11 May 2011 13:23:21 -0700 > Yinghai Lu <[email protected]> wrote: > >> On 05/09/2011 02:35 PM, Jesse Barnes wrote: >>> On Sun, 08 May 2011 11:54:32 -0700 >>> Yinghai Lu <[email protected]> wrote: >>> >>>> >>>> Need to use it in _e1000e_disable_aspm. >>>> when aer happens, >>>> pci_walk_bus already have down_read(&pci_bus_sem)... >>>> then report_slot_reset >>>> ==> e1000_io_slot_reset >>>> ==> e1000e_disable_aspm >>>> ==> pci_disable_link_state... >>>> >>>> We can not use pci_disable_link_state, and it will try to hold pci_bus_sem >>>> again. >>>> >>>> Try to have __pci_disable_link_state that will not need to hold >>>> pci_bus_sem. >>> >>> What about the other callers of e1000e_disable_aspm? Do they already >>> have the lock held or is it just reset that needs the already locked >>> version? >> >> yes. >> >> there is another version when aspm is not defined. and it does not use any >> lock. >> >> #ifdef CONFIG_PCIEASPM >> static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state) >> { >> pci_disable_link_state(pdev, state); >> } >> #else >> static void __e1000e_disable_aspm(struct pci_dev *pdev, u16 state) >> { >> int pos; >> u16 reg16; >> >> /* >> * Both device and parent should have the same ASPM setting. >> * Disable ASPM in downstream component first and then upstream. >> */ >> pos = pci_pcie_cap(pdev); >> pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, ®16); >> reg16 &= ~state; >> pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16); >> >> if (!pdev->bus->self) >> return; >> >> pos = pci_pcie_cap(pdev->bus->self); >> pci_read_config_word(pdev->bus->self, pos + PCI_EXP_LNKCTL, ®16); >> reg16 &= ~state; >> pci_write_config_word(pdev->bus->self, pos + PCI_EXP_LNKCTL, reg16); >> } >> #endif > > No, I mean __e1000e_disable_aspm is called from several spots: > > *** drivers/net/e1000e/82571.c: > e1000_get_variants_82571[435] e1000e_disable_aspm(adapter->pdev, > PCIE_LINK_STATE_L0S); > > *** drivers/net/e1000e/netdev.c: > e1000_change_mtu[5027] e1000e_disable_aspm(adapter->pdev, > PCIE_LINK_STATE_L1); > __e1000_resume[5402] e1000e_disable_aspm(pdev, PCIE_LINK_STATE_L1); > e1000_io_slot_reset[5650] e1000e_disable_aspm(pdev, PCIE_LINK_STATE_L1); > e1000_probe[5797] e1000e_disable_aspm(pdev, PCIE_LINK_STATE_L1); > > Are all of them safe for the unlocked version of ASPM disable?
yes, there are two version __e1000e_disable_aspm(), one is when aspm support is compiled in, and another one is not. the one without aspm compiled does not use pci_bus_sem in it self... So I assume another path should not use pci_bus_sem in the function itself. Yinghai ------------------------------------------------------------------------------ Achieve unprecedented app performance and reliability What every C/C++ and Fortran developer should know. Learn how Intel has extended the reach of its next-generation tools to help boost performance applications - inlcuding clusters. http://p.sf.net/sfu/intel-dev2devmay _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
