Bug#681280: kernel warning at .../net/sched/sch_generic.c:255 dev_watchdog - eth0 (sky2) transmit queue 0 timed out

[Jonathan Nieder <jrnieder@gmail.com>]

Jonathan Nieder wrote:
> Julian Gilbey wrote [regarding sky2 tx stalls]:

>> I think this may be a hardware fault: I have now identified what
>> appears to be the physical situation under which this bug manifests
>> itself: it reliably occurs when I attempt to connect to an ethernet
>> without my power supply connected (i.e., running from the battery),
>> and never seems to occur when I am on main power.
>
> Weird.  How reproducible is this?  Does passing sky2.legacy_pme=1 on
> the kernel command line help?

Scratch that.  The legacy_pme setting should only affect wake-on-LAN.

The only interesting recent sky2 patch I can find upstream is
v3.6-rc1~125^2~264 (sky2: Fix for interrupt handler, 2012-07-03).  How
does a kernel with that patch applied behave?

A 3.6.y kernel should be hitting experimental this weekend, or
if you'd like to try the patch before then, see [1].

Thanks again for your help and sorry for the slow reply.

Sincerely,
Jonathan

[1] http://kernel-handbook.alioth.debian.org/ch-common-tasks.html#s4.2.2

From: Mirko Lindner <mlindner@marvell.com>
Date: Tue, 3 Jul 2012 23:38:46 +0000
Subject: sky2: Fix for interrupt handler

commit d663d181b9e92d80c2455e460e932d34e7a2a7ae upstream.

Re-enable interrupts if it is not our interrupt

Signed-off-by: Mirko Lindner <mlindner@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 drivers/net/ethernet/marvell/sky2.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c
index 11ddd8383315..69fc888c09e9 100644
--- a/drivers/net/ethernet/marvell/sky2.c
+++ b/drivers/net/ethernet/marvell/sky2.c
@@ -3060,8 +3060,10 @@ static irqreturn_t sky2_intr(int irq, void *dev_id)
 
 	/* Reading this mask interrupts as side effect */
 	status = sky2_read32(hw, B0_Y2_SP_ISRC2);
-	if (status == 0 || status == ~0)
+	if (status == 0 || status == ~0) {
+		sky2_write32(hw, B0_Y2_SP_ICR, 2);
 		return IRQ_NONE;
+	}
 
 	prefetch(&hw->st_le[hw->st_idx]);
 
-- 
1.8.0.rc3