[PATCH v3 3/3] ucc_geth: Fix hangs after switching from full to half duplex

[David Miller]

From: Anton Vorontsov <avorontsov at ru.mvista.com>
Date: Fri, 11 Sep 2009 01:48:12 +0400

> MPC8360 QE UCC ethernet controllers hang when changing link duplex
> under a load (a bit of NFS activity is enough).
> 
>   PHY: mdio at e0102120:00 - Link is Up - 1000/Full
>   sh-3.00# ethtool -s eth0 speed 100 duplex half autoneg off
>   PHY: mdio at e0102120:00 - Link is Down
>   PHY: mdio at 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 at ru.mvista.com>

Applied.