Messages in this thread | | | Date | Thu, 11 Jul 2013 22:43:01 -0400 | From | Don Dutile <> | Subject | Re: [PATCH -v2 1/3] PCI: introduce PCIe Device Serial Number Capability support |
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On 07/11/2013 09:38 PM, Yijing Wang wrote: > Hi Don, > Thanks for your review and comments very much! > >>> + dev->sn = pci_device_serial_number(dev); >>> + >> Finally, 'the comment below': >> I know you were following Bjorn's suggestion, which I thought >> was an improvement, but why not do above assignment in pci_device_serial_number() ? > > I don't do assignment in pci_device_serial_number() because pci_device_serial_number() > is an EXPORT_SYMBOL, and will be used to get dsn for non-scaned device, for example: > > 1. we have pcie device in slot before suspend. > 2. we removed the device during suspend. > 3. we reinserted a new device during suspend. > 4. we should check the device change during resume, so we > try to use pcie device serial number to identify changes. > But the pci_dev structure maybe the old stale data. So > I prefer to get dsn by return. > > what about this: > > static void pci_init_capabilities(struct pci_dev *dev) > ........ > pci_dsn_init(dev); > .......... > > > void pci_dsn_init(dev) > { > dev->sn = pci_device_serial_number(dev); > } > > > Looks good! I think that meets all the uses (use in init, post-suspend). - Don
>> See above.... >> - Don >> >>> /* Vital Product Data */ >>> pci_vpd_pci22_init(dev); >>> >>> diff --git a/include/linux/pci.h b/include/linux/pci.h >>> index 0fd1f15..10d190b 100644 >>> --- a/include/linux/pci.h >>> +++ b/include/linux/pci.h >>> @@ -342,6 +342,7 @@ struct pci_dev { >>> struct list_head msi_list; >>> struct kset *msi_kset; >>> #endif >>> + u64 sn; /* device serieal number, 0 if not support */ >>> struct pci_vpd *vpd; >>> #ifdef CONFIG_PCI_ATS >>> union { >>> @@ -995,6 +996,8 @@ ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf); >>> ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf); >>> int pci_vpd_truncate(struct pci_dev *dev, size_t size); >>> >>> +u64 pci_device_serial_number(struct pci_dev *dev); >>> + >>> /* Helper functions for low-level code (drivers/pci/setup-[bus,res].c) */ >>> resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx); >>> void pci_bus_assign_resources(const struct pci_bus *bus); >> >> >> . >> > >
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