Under load, sky2 causes the system to hang.  The only output on the console is
the following:

[55022.353219] NETDEV WATCHDOG: eth0: transmit timed out
[55022.358356] sky2 eth0: tx timeout
[55022.361753] sky2 status report lost?

The problem exists in all kernels I've tested: 2.6.17 through 2.6.19-rc6-mm2. 
Every now and again the network device will crash, but won't take the system
down with it, and I'm able to recover with rmmod sky2 / modprobe sky2. If the
system does crash, after a reset, sky2 does not come up properly, but unloading
and reloading the module will recover it.

There is no appreciable difference with receive checksums disabled.   

The device:

02:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8053 PCI-E Gigabit
Ethernet Controller (rev 20)
        Subsystem: ASUSTeK Computer Inc. Marvell 88E8053 Gigabit Ethernet
controller PCIe (Asus)
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR-
        Latency: 0, Cache Line Size: 16 bytes
        Interrupt: pin A routed to IRQ 315
        Region 0: Memory at fa9fc000 (64-bit, non-prefetchable) [size=16K]
        Region 2: I/O ports at c800 [size=256]
        Expansion ROM at fa9c0000 [disabled] [size=128K]
        Capabilities: [48] Power Management version 2
                Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA
PME(D0+,D1+,D2+,D3hot+,D3cold+)
                Status: D0 PME-Enable- DSel=0 DScale=1 PME-
        Capabilities: [50] Vital Product Data
        Capabilities: [5c] Message Signalled Interrupts: Mask- 64bit+ Queue=0/1
Enable+
                Address: 00000000fee0300c  Data: 41a1
        Capabilities: [e0] Express Legacy Endpoint IRQ 0
                Device: Supported: MaxPayload 128 bytes, PhantFunc 0, ExtTag-
                Device: Latency L0s unlimited, L1 unlimited
                Device: AtnBtn- AtnInd- PwrInd-
                Device: Errors: Correctable- Non-Fatal- Fatal- Unsupported-
                Device: RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop-
                Device: MaxPayload 128 bytes, MaxReadReq 512 bytes
                Link: Supported Speed 2.5Gb/s, Width x1, ASPM L0s, Port 0
                Link: Latency L0s <256ns, L1 unlimited
                Link: ASPM Disabled RCB 128 bytes CommClk+ ExtSynch-
                Link: Speed 2.5Gb/s, Width x1

This is the onboard ethernet on ASUS P5W-DH Deluxe.  I am only using one of the
ethernet ports, the other is disabled in the BIOS.