smsc0 driver on rpi2

[Andreas Schwarz]

On 21.05.15, Andreas Andersson wrote:

> smsc0: warning: MII is busy
> smsc0: warning: Failed to read register 0x114
> smsc0: warning: MII read timeout
> smsc0: warning: Failed to read register 0x114
> smsc0: warning: MII is busy
>
> This happends when the rpi2 has been turned on for some while. And the
> raspberry becomes pretty slow and laggy when this error occurs. CPU when
> looking at top is pretty much idle across all cores, but load averages
> are: 7:23AM  up 13:51, 5 users, load averages: 3.70, 3.37, 3.24

Seems that I'm running into the same problem with one of my rpi2 (r283859). 
It will occur when having high IO, typically when building the world. I'm 
also running a rpi2 with older r283161, which is not affected.

-asc