Happy Meal lockups on Ultra 5

[Jan Houstek <houstek-lists@utf.troja.mff.cuni.cz>]

Hi all.

I turned one Ultra 5 machine from a terminal into a FTP server. But after
about 20s of downloading a large file eth0 locks for about 30s and kernel
says 'NETDEV WATCHDOG: eth0 transmit timed out' and than resets the NIC.

Similar problems were havily discussed in lists (this one too) and the
only solution was an one-liner patch from Jorge Rivas <jrivas@cisgalicia.org>.

//---------------------------------------------------------------------
--- drivers/net/sunhme.c.orig
+++ drivers/net/sunhme.c
@@ -1983,6 +1983,7 @@
        }
        hp->tx_old = elem;
        TXD((">"));
+ udelay(1);

        if (netif_queue_stopped(dev) &&
            TX_BUFFS_AVAIL(hp) > (MAX_SKB_FRAGS + 1))

//---------------------------------------------------------------------

I applied it (against 2.4.21 vanilla) and the problems disappeared.
Moreover, the throughput raised by about 10%. So I just want to report
that this is not only Ultra1 issue.

-- Honza Houstek