From: Petri Lehtinen on
From: Anton Vorontsov <avorontsov(a)>

Since commit 864fdf884e82bacbe8ca5e93bd43393a61d2e2b4 ("ucc_geth:
Fix hangs after switching from full to half duplex") ucc_geth driver
disables the controller during MAC configuration changes. Though,
disabling the controller might take quite awhile, and so the netdev
watchdog might get upset:

NETDEV WATCHDOG: eth2 (ucc_geth): transmit queue 0 timed out
------------[ cut here ]------------
Badness at c02729a8 [verbose debug info unavailable]
NIP: c02729a8 LR: c02729a8 CTR: c01b6088
REGS: c0451c40 TRAP: 0700 Not tainted (2.6.32-trunk-8360e)
NIP [c02729a8] dev_watchdog+0x280/0x290
LR [c02729a8] dev_watchdog+0x280/0x290
Call Trace:
[c0451cf0] [c02729a8] dev_watchdog+0x280/0x290 (unreliable)
[c0451d50] [c00377c4] run_timer_softirq+0x164/0x224
[c0451da0] [c0032a38] __do_softirq+0xb8/0x13c
[c0451df0] [c00065cc] do_softirq+0xa0/0xac
[c0451e00] [c003280c] irq_exit+0x7c/0x9c
[c0451e10] [c00640c4] __ipipe_sync_stage+0x248/0x24c

This patch fixes the issue by detaching the netdev during the
time we change the configuration.

Reported-by: Lennart Sorensen <lsorense(a)>
Signed-off-by: Anton Vorontsov <avorontsov(a)>
Tested-by: Lennart Sorensen <lsorense(a)>
Cc: Stable <stable(a)> [2.6.32]
Signed-off-by: David S. Miller <davem(a)>

(cherry picked from commit 08b5e1c91ce95793c59a59529a362a1bcc81faae)
drivers/net/ucc_geth.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 20aa5b5..5077fd9 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -1563,7 +1563,10 @@ static int ugeth_disable(struct ucc_geth_private *ugeth, enum comm_dir mode)

static void ugeth_quiesce(struct ucc_geth_private *ugeth)
- /* Wait for and prevent any further xmits. */
+ /* Prevent any further xmits, plus detach the device. */
+ netif_device_detach(ugeth->ndev);
+ /* Wait for any current xmits to finish. */

/* Disable the interrupt to avoid NAPI rescheduling. */
@@ -1577,7 +1580,7 @@ static void ugeth_activate(struct ucc_geth_private *ugeth)
- netif_tx_wake_all_queues(ugeth->ndev);
+ netif_device_attach(ugeth->ndev);

/* Called every time the controller might need to be made

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