[realtek] setting autoconf speed to 10 even with reboot?

[Donald Becker]

On Tue, 6 Feb 2001, Daniel Harker wrote:

> I am using the Dlink-538DFE ethernet card and using the rtl8139 kernel 
> driver.

Which driver version?

> When it loads on my computer it autonegotiates to 100base.  My network only 
> works on 10base, or else I get errors.
> 
> How do I set it permenantly to 10baseT?  I got the mii-diag program and 
> types mii-diag -A 10baseT, but it only went down to 10baseT until I 
> rebooted... then it went right back to 100base.

That's the defined semantics of setting the media with "mii-diag".  It
only retains the setting until the transceiver is reset.

I _recommend_ using 'mii-diag' to set the advertised values.

The methods below will disable autonegotiation when forcing the speed
and duplex, which .  Disabling autonegotation leads to future
configuration problems, and disables features such as flow control.

> IS there some command with mii-diag that can write the eeprom permenently?

No, not with 'mii-diag'.
The 'rtl8139-diag' program is used to write the EEPROM.

The transceiver configuration by is at byte offset 0x0c (the lower byte
at word offset 6).  Bits 5, 4 and 0 (0x31) are mapped to bits 13, 12 and
8 (0x3100) of the transceiver control register.  The current code in
rtl8139-diag.c will not write this register, but it would be trivial to
add around line 594.  Note: I do not recommend this!
____
	if (new_default_media) {
		int new_media = eeprom_contents[6] & ~0x0031;
		switch (new_default_media) {
		case 0x0000: new_media |= 0x0000; break;   /* 10baseT */
		case 0x0204: new_media |= 0x0001; break;   /* 10baseT-FDX */
		case 0x0003: new_media |= 0x0020; break;   /* 100baseTx */
		case 0x0205: new_media |= 0x0021; break;   /* 100baseTx-FDX */
		case 0x0800: new_media |= 0x0011; break;   /* Autosense */
		default: new_media = eeprom_contents[6];   /* Unchanged */
		}
		do_update(ioaddr, eeprom_contents, 6, "Default Media",
				  (new_hwaddr[i*2]<<8) + new_hwaddr[i*2+1]);
	}
____

> Is there some other way to set the autonegotiation abilities down?  Can I 
> use a kernel option?  If so, what is it?

Yes.  You may use driver v1.13 and force the transceiver speed with a
module option.  Bit 0x20 sets the speed, and bit 0x10 set the duplex.
    10baseT	options=0x01
    10baseT-FDX	options=0x10
The driver will emit a "Forcing speed to ...." when you set this.

I'll likely change these options to more logical values.  Perhaps
   0x10  10baseT
   0x20  10baseTx-FDX
   0x100  100baseTx
   0x200  100baseTx-FDX
Any suggestions on indicating autonegotiation-advertising vs. forcing?

Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993