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Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?


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Old 01-16-2006, 10:43 PM   #1
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Unhappy NIC inits at 100MB; won't at 1GB w/o first plugging in 100MB cable!

OK, this is weird. I have a couple of older Supermicro boxes that I host for a client of mine. Their P4DP8-G2 boards have dual 10/100/1000 NICs. Here's the odd thing: the NIC ports won't init when plugged into a 1GB switch (no link light at all)--but they will if you plug in a 100MB cable, let the link light come on, then take it out, and plug in the 1GB cable (the link LED is green for 100MB; orange for 1GB; so it's clear that it's really switching speeds when I swap cables--and tests verify the difference in throughput).

One of the boxes is running Windows and the driver there let's me force it to a max speed of 100MB and the init works with the 1GB cable at that setting, but, of course, I'm running at 100MB. I don't see any simple way to do the same thing in Redhat ES 3, but I really need the 1GB speed anyway on the RH box because it handles a big disk array that's used for backups.

Redhat says the on-board NICs are:
Intel 82546EB Gigabit chips

I've wondered about updating the BIOS, but I'm sort of waiting to see if Supermicro's support folks think that might do any good. (It seems like that's sort of the wrong level for it to be of any use--more of a driver problem, right?)

The Intel info on the latest Linux driver for the e1000-type cards lists a bunch of options for use with modprobe or insmode. Right now, the loading of the driver is (apparently--I'm a little fuzzy on how all this works) being handled by these lines in /etc/modules.conf

alias eth0 e1000
alias eth1 e1000

Is there another level of indirection here that defines e1000--where I could maybe stick some parameters? Or, how would I switch to using modprobe or insmode so that I can try specifying the speed as 1000 as a parameter (as per the Intel instructions)?

Also, if that didn't work, is there a way to load the driver with the speed at 100MB as the max and then switch it to 1000MB? (As it seems like this might work from the "put in the 100 to make it happy then put in the 1GB cable" approach that I discovered rather by accident--I've got a 100MB switch on the firewall and a 1GB switch for the private LAN so it happened because I switched the cables trying to figure out why the one showed a link and the other didn't. Having to be on hand to do this each time there's a reset is not terribly practical....)

BTW, it sounds like you have to make the actual driver after you download the goo from Intel--great if you're into that sort of thing, but I'd rather not be. If the instructions say to do:

make install

in the directory where the download got unzipped, do I need the gnu compiler stuff loaded on the box--or what? Is this one from Intel actually likely to be a newer version of the driver than what comes with the kernel (I've got the latest one from RH--2.4.21-37.ELsmp)? Is there any way to find revision info from the driver itself?

Thanks for any help you can offer! Sorry about the boat load of questions.... :~\

Old 01-16-2006, 11:49 PM   #2
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If you use /sbin/modinfo e1000, you will see the options to pass to the module. To set them up every time the e1000 module is loaded add options e1000 [options 1] [options 2] to /etc/modules.conf. There is the ifconfig way and another way is included in the e1000 module to the NIC cards to 1000 Mb (megabit).

There is no such thing as 1000 Mb (megabit) ethernet cable. CAT-5e can be used with 1000 Mb networks with no problems. There is CAT-6 but it costs more than CAT-5e.

BTW, I can not believe that a Linux admin does not know modinfo and/or ifconfig because I know these utilities and I use Linux as a home desktop OS.
Old 01-17-2006, 01:11 PM   #3
Registered: Feb 2003
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Hi Electro,

The options to pass to the module are nicely documented in the Intel docs, thanks. Are you saying that I can put them right on the existing alias line in /etc/modules.conf?

There is the ifconfig way and another way is included...
This doesn't help much, I'm afraid. An explanation or a pointer toward some docs that address things beyond a basic setup would be great.

There is no such thing as a 1000 Mb ... cable
Sorry for my imprecise explanation--what I'm referring to is a cable whose other end is plugged into a 1000 Mb switch (as opposed to one plugged into a 100 Mb switch); that is, it's nothing to do with the cable per se, but what the other end is attached to.

BTW, I can not believe that a Linux admin does not know...
Well, my ignorance isn't in dispute here--whether you believe it or not. I do happen to be fluent enough with the DBMS (and the application that it supports) that this box is hosting that my clients get good value for their money. Maybe you'd be so good as to point me toward some good docs for these utilities--particularly any that go beyond basic setups? Or explain a way to load the driver at 100Mb and then switch it to 1 Gb...?

With regard to your surprise, despite working with Linux for quite some time, I've never had to resort to anything beyond the basic setup for NICs so I have not had occassion to do anything with this aspect of things. I don't claim to be "a Linux admin"--except by default.

And, although, I have been working with networked computers using many different operating systems for many, many years, this particular behavior is a new one on me. So, how would you advise I deal with a NIC port that will init at low speed, but not at full speed unless you first connect it to a slower speed switch?

Old 01-17-2006, 07:50 PM   #4
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Originally Posted by Electro
BTW, I can not believe that a Linux admin does not know modinfo and/or ifconfig because I know these utilities and I use Linux as a home desktop OS.
Let's please keep the discussion focused on the topic at hand, as these kinds of editorial comments don't really help move the discussion forward. Everyone has different levels of experience, and what might be basic or obvious to one person may not be to another. Thanks


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