I have BCM5906 ethernet card and there is stable problem with it: link goes down with network hungry apps such as distcc or nfs and I can't get it back to normal until I reinsert tg3 module. This card have had this problem before but it has been fixed. There is nothing in dmesg that cant tell you there is a problem, card simply became unusable. With kernel <=2.6.39 card works as expected

here is my lspci -v:
10:00.0 Ethernet controller: Broadcom Corporation NetLink BCM5906M Fast Ethernet PCI Express (rev 02)
	Subsystem: Hewlett-Packard Company Device 30c2
	Flags: bus master, fast devsel, latency 0, IRQ 43
	Memory at d0000000 (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 00-1a-4b-ff-fe-89-b5-6a
	Kernel driver in use: tg3
	Kernel modules: tg3