[realtek] Rtl8139 file transmission lockup

[Donald Becker]

On Sat, 3 Aug 2002, Sean Mullen wrote:

>    I'm using 2 RTL8139 cards (both are SMC 1211TX) on my linux firewall.
> These are on a linux box with kernel linux-2.4.16.  Normal internet traffic
> from my local LAN is fine.  However, when I'm transferring files off of the
> linux box to a Win 2k box on the local LAN, the eth1 (LAN facing) interface
> locks with a TX error (assuming it's speed related).

What driver version are you using?

>    I can re-enable the LAN with an 'ifdown eth1' and an 'ifup eth1'.  I
> added a debug printout for a TX underrun, I think that's what's happening.
> 
>    Here's the result of thedebug line I added: "eth1:TxUnderrun, status
> 0008e52e."

That is reporting a transmit underrun.
This should be a mostly harmless event.
  The transmitted packet might be corrupted, with a assured-bad CRC.
  The Tx FIFO threshold will be increased
  The transmitter will be restarted.

The initial Tx threshold value is set to 256 bytes (see TX_FIFO_THRESH below)
The threshold is increased by 64 bytes at each underrun.

This initial value is set by the following documented constant:

/* PCI Tuning Parameters
   Threshold is bytes transferred to chip before transmission starts. */
#define TX_FIFO_THRESH 256	/* In bytes, rounded down to 32 byte units. */


> Index #2: Found a RealTek RTL8139 adapter at 0xec00.
> RealTek chip registers at 0xec00
>  0x000: ... ... ... ...  000aa52e 000aa52e 000aa52e 000aa52e

Hmmm, none of the Tx status registers are reporting a Tx underrun here.

>  0x020: 02f70010 02f71010 02f72010 02f73010 02f60000 0d0a0000 654c653c
> 0000c07f

And this reports that the transmitter and receiver are both enabled.

>  0x040: 74000400

The transmitter configuration is normal
  74.. ....	Version 74 == 8139C
  .... .4..	256 bytes per burst

>  0x060: 1100f00f 01e1782d 000145e1 00000000 00000004 000417c8 b0f243b9

-- 
Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
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