linux下可通过/sys/bus/pci/devices/0000\:[bus number]\:[device number].[function number]/ 目录下的节点进行热拔插操作。

板子上电前PCIe插槽有一块NVME的固态硬盘

[ 0.198515] pci 0000:00:00.0: [16c3:abcd] type 01 class 0x060400

[ 0.199284] pci 0000:01:00.0: [126f:2263] type 00 class 0x010802

[ 8.161374] nvme nvme0: pci function 0000:01:00.0

[ 8.166407] nvme 0000:01:00.0: enabling device (0000 -> 0002)

# ls /sys/bus/pci/devices/0000\:01\:00.0

broken_parity_status enable rescan

class irq reset

config local_cpulist resource

consistent_dma_mask_bits local_cpus subsystem

device modalias subsystem_device

devspec msi_bus subsystem_vendor

dma_mask_bits power uevent

driver_override remove vendor

现在需要在板子保持开机运行的状态下，先取下NVME的固态硬盘，再换上一块PCIe 网卡，并让网卡正常工作。

remove 原有设备，然后lspci查看， 0000:01:00.0: [126f:2263]已经不见了

# echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/remove

#

# lspci

00:00.0 Class 0604: 16c3:abcd

现在可以从插槽取下固态硬盘，插上网卡

通过上游bus进行rescan

echo 1 > /sys/bus/pci/devices/0000\:00\:00.0/rescan

[ 72.436704] pci 0000:00:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring

[ 72.445041] pci 0000:01:00.0: [10ec:8168] type 00 class 0x020000

[ 72.451319] pci 0000:01:00.0: reg 0x10: initial BAR value 0x00000000 invalid

[ 72.458380] pci 0000:01:00.0: reg 0x10: [io size 0x0100]

[ 72.464113] pci 0000:01:00.0: reg 0x18: [mem 0x00000000-0x00000fff 64bit]

[ 72.471112] pci 0000:01:00.0: reg 0x20: [mem 0x00000000-0x00003fff 64bit]

[ 72.479299] pci 0000:01:00.0: supports D1 D2

[ 72.483583] pci 0000:01:00.0: PME# supported from D0 D1 D2 D3hot D3cold

[ 72.490667] pci_bus 0000:01: busn_res: [bus 01] end is updated to 01

[ 72.497090] pci 0000:00:00.0: BAR 7: assigned [io 0x1000-0x1fff]

[ 72.503202] pci 0000:01:00.0: BAR 4: assigned [mem 0xf1100000-0xf1103fff 64bit]

[ 72.510683] pci 0000:01:00.0: BAR 2: assigned [mem 0xf1104000-0xf1104fff 64bit]

[ 72.518162] pci 0000:01:00.0: BAR 0: assigned [io 0x1000-0x10ff]

# [ 72.569018] r8169 0000:01:00.0: no of_node; not parsing pinctrl DT

[ 72.575313] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded

[ 72.580996] r8169 0000:01:00.0: enabling device (0000 -> 0003)

[ 72.603261] r8169 0000:01:00.0 eth1: RTL8168h/8111h at 0xc8ea0000, e8:4e:06:72:f5:8a, XID 14100800 IRQ 66

[ 72.612886] r8169 0000:01:00.0 eth1: jumbo features [frames: 9200 bytes, tx checksumming: ko]

[ 72.846167] r8169 0000:01:00.0: Direct firmware load for rtl_nic/rtl8168h-2.fw failed with error -2

[ 72.855262] r8169 0000:01:00.0 eth1: unable to load firmware patch rtl_nic/rtl8168h-2.fw (-2)

[ 72.876122] r8169 0000:01:00.0 eth1: link down

查看新的网卡设备，多了一个eth1

# lspci

00:00.0 Class 0604: 16c3:abcd

01:00.0 Class 0200: 10ec:8168

#

#

# ifconfig

eth0 Link encap:Ethernet HWaddr 02:67:AB:81:02:BB

UP BROADCAST MULTICAST MTU:1500 Metric:1

RX packets:0 errors:0 dropped:0 overruns:0 frame:0

TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

Interrupt:16

eth1 Link encap:Ethernet HWaddr E8:4E:06:72:F5:8A

UP BROADCAST MULTICAST MTU:1500 Metric:1

RX packets:0 errors:0 dropped:0 overruns:0 frame:0

TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

lo Link encap:Local Loopback

inet addr:127.0.0.1 Mask:255.0.0.0

UP LOOPBACK RUNNING MTU:65536 Metric:1

RX packets:0 errors:0 dropped:0 overruns:0 frame:0

TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1

RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)