puzzle about the pci_add_child

[M. Warner Losh]

In message: <87ab37ab0511280850y1bca554n1da9b11c321be34b at mail.gmail.com>
            kylin <fierykylin at gmail.com> writes:
:  i am reading the pci code of freeBSD 53 ,and come to the puzzle of
:    pci_add_child.
:    1
:     why should we =09pci_cfg_save(dinfo->cfg.dev, dinfo, 0); after we have
:    already fill the cfg in pci_read_device ?

It hasn't been completely filled in by pci_read_device.

:    2
:    what 's the purpose of the function couple
:    pci_cfg_save(dinfo->cfg.dev, dinfo, 0);
:    pci_cfg_restore(dinfo->cfg.dev, dinfo)
:    below is the function ,thank u

Power state gets set to D0 as a side effect so that the device is live
for the probe.

Warner