Re: [PATCH] Unbreak sky2 on 88E8039 with current git

From: Petr Vandrovec
Date: Sat Feb 02 2008 - 20:22:58 EST


Stephen Hemminger wrote:
On Sat, 2 Feb 2008 11:52:43 +0100
Petr Vandrovec <petr@xxxxxxxxxxxxxx> wrote:

Hello,
since I synced my tree to Linus's one two days ago, sky2's packet receiption
dies almost instantly. Device still transmits packets, but no receive. Fortunately fix is simple, unfortunately I do not know why fix works...

Commit f03b865491c2f30f2a4d77cdafc69c978ceb38a0 (sky2: align IP header on Rx
if possible) stopped aligning receive buffers on devices which do not need
HANG_CHECK. Unfortunately there is at least one device (mine, Yukon FE, rev 3)
which is not happy if receive buffer is not aligned. I have no idea which
other chips/revisions are affected as well.

Without patch 'ping -f -b 192.168.101.255' RX count stops incrementing in less
than 50 packets. With patch in place it can run like before, for hours...
Box is an AMD rev F processor, with nVidia's MCP61 chipset.
Petr

I don't have a Yukon FE, but I believe that the Yukon FE does have a ram
buffer, so you HANG_CHECK should be enabled for that device. You can check
by running:
ethtool -d eth0 | grep 'Ram Buffer'
With ram buffer (like XL, EC)

# ethtool -d eth0 | grep 'Ram Buffer'
Ram Buffer 0x18

No ram buffer (like EC-U, FE+, ...)
# ethtool -d eth0 | grep 'Ram Buffer'
Ram Buffer 0x00

Some small one (if it is size):

gwy:~# ethtool -d eth0 | grep 'Ram'
Ram Buffer 0x01

I've never observed hang on that device, and I have it for over year. I stress it sufficiently to kill EC rev 2 I have in the notebook when I copy some data between these two boxes, but this FE never hung.
Petr

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