MPC8360 QE UCC ethernet controllers hang when changing link duplex
under a load (a bit of NFS activity is enough).
PHY: mdio@e0102120:00 - Link is Up - 1000/Full
sh-3.00# ethtool -s eth0 speed 100 duplex half autoneg off
PHY: mdio@e0102120:00 - Link is Down
PHY: mdio@e0102120:00 - Link is Up - 100/Half
NETDEV WATCHDOG: eth0 (ucc_geth): transmit queue 0 timed out
------------[ cut here ]------------
Badness at c01fcbd0 [verbose debug info unavailable]
NIP: c01fcbd0 LR: c01fcbd0 CTR: c0194e44
...
The cure is to disable the controller before changing speed/duplex
and enable it afterwards.
Though, disabling the controller might take quite a while, so we
better not grab any spinlocks in adjust_link(). Instead, we quiesce
the driver's activity, and only then disable the controller.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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