Guest network down with version 5.2 and e1000

[FixItDad]

After an upgrade from 5.1.38-122592 to 5.2.20-125813 the guest network did not automatically come up. The network worked fine after bringing the interface down/up. Another copy of the same VM running on different hardware with identical software did not have the problem.

Both VMs were using E1000 network adapters in bridged mode. Switching to either of the PCnet adapters fixed the issue on the "not working" system.

[Beware: User speculation] The not working system is slower and it looks like there was a recent change to the E1000 LinkUpDelay from 5000ms to 3000ms. I'm suspecting that the shortened delay may be related to the problem. I could not find a configuration setting for the LinkUpDelay.

Host systems: Debian 9 (stable) 64 bit (fully up to date)

Guest systems: Debian 9 32 bit (fully up to date)

About the VirtualBox version. I first noticed the issue on 5.2.20, but did not have a chance to gather logs until after upgrading to 5.2.22. Both versions have the issue.

Not working hardware:

  AMD Turion(tm) 64 Mobile Technology ML-34 (800 MHz single core)  
  Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8100/8101L/8139 PCI Fast Ethernet Adapter (rev 10)
	Subsystem: Hewlett-Packard Company RTL-8100/8101L/8139 PCI Fast Ethernet Adapter
	Flags: bus master, medium devsel, latency 128, IRQ 22, NUMA node 0
	I/O ports at a000 [size=256]
	Memory at c020a400 (32-bit, non-prefetchable) [size=256]
	Capabilities: [50] Power Management version 2
	Kernel driver in use: 8139too
	Kernel modules: 8139cp, 8139too

Working hardware:

  Intel(R) Core(TM)2 Duo CPU T7100 @ 1.80GHz (dual core, 800 MHz)  
  Ethernet controller: Broadcom Limited NetLink BCM5787M Gigabit Ethernet PCI Express (rev 02)
	Subsystem: Hewlett-Packard Company 6710b
	Physical Slot: 1
	Flags: bus master, fast devsel, latency 0, IRQ 30
	Memory at e4000000 (64-bit, non-prefetchable) [size=64K]
	Expansion ROM at <ignored> [disabled]
	Capabilities: [48] Power Management version 3
	Capabilities: [50] Vital Product Data
	Capabilities: [58] Vendor Specific Information: Len=78 <?>
	Capabilities: [e8] MSI: Enable+ Count=1/1 Maskable- 64bit+
	Capabilities: [d0] Express Endpoint, MSI 00
	Capabilities: [100] Advanced Error Reporting
	Capabilities: [13c] Virtual Channel
	Capabilities: [160] Device Serial Number 00-1c-c4-ff-fe-c9-02-6d
	Capabilities: [16c] Power Budgeting <?>
	Kernel driver in use: tg3
	Kernel modules: tg3

[FixItDad]

logs. "after"= after restarting network interface.

[FixItDad]

Logs of system without the issue for comparison.