Messages in this thread Patch in this message | | | Date | Fri, 12 Jul 2013 09:38:04 +0800 | From | Yijing Wang <> | Subject | Re: [PATCH -v2 1/3] PCI: introduce PCIe Device Serial Number Capability support |
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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); }
> 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); > > > . >
-- Thanks! Yijing
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