tg3 'No PHY devices' loading issue

[Josh Boyer <jwboyer@redhat.com>]

Hi Matt and Michael,

I'm seeing an odd issue with the tg3 driver on one of my development
machines.  I've tried kernels 3.2.10, 3.3.0, 3.3.1, 3.3.2 and 3.4-rc3
and they all seem to exhibit this issue now.  When the machine boots
and the tg3 driver is loaded, it fails to find a PHY and then reports
'Problem fetching invariants of chip'.  If I do a rmmod/modprobe of
tg3 after login, the probe seems to work fine and ethernet works as
expected.  You can see this in the dmesg below:

[jwboyer@vader ~]$ dmesg | grep tg3
[    2.084969] tg3.c:v3.122 (December 7, 2011)
[    2.093511] tg3 mdio bus: probed
[    2.093513] tg3 0000:03:00.0: No PHY devices
[    2.093531] tg3 0000:03:00.0: Problem fetching invariants of chip, aborting
[   90.824697] tg3.c:v3.122 (December 7, 2011)
[   90.857068] tg3 mdio bus: probed
[   90.862540] tg3 0000:03:00.0: eth0: Tigon3 [partno(BCM57788) rev 57780001] (PCI Express) MAC address 18:03:73:e6:01:88
[   90.862547] tg3 0000:03:00.0: eth0: attached PHY driver [Broadcom BCM57780] (mii_bus:phy_addr=300:01)
[   90.862552] tg3 0000:03:00.0: eth0: RXcsums[1] LinkChgREG[0] MIirq[0] ASF[0] TSOcap[1]
[   90.862557] tg3 0000:03:00.0: eth0: dma_rwctrl[76180000] dma_mask[64-bit]
[   90.919961] tg3 0000:03:00.0: irq 47 for MSI/MSI-X
[   91.863311] tg3 0000:03:00.0: p3p1: Link is down
[   92.864348] tg3 0000:03:00.0: p3p1: Link is up at 100 Mbps, full duplex
[   92.864352] tg3 0000:03:00.0: p3p1: Flow control is on for TX and on for RX

It has worked on some of the older kernels without the need for the
manual rmmod/modprobe step, so it seems to be somewhat timing related.
I'm not sure if there is a module load ordering issue, but that doesn't
seem to be the case.  I can't explain why a later modprobe would work
just fine though.

Do you have any thoughts on how to go about debugging/fixing this?  I'd
be happy to test and provide whatever information you need.

josh