Date: Thu, 19 Jan 1995 10:43:38 +0100 From: Andres Vega Garcia <Andres.Vega_Garcia@sophia.inria.fr> To: awd@ddg.com (Andrew W. Donoho) Cc: questions@FreeBSD.org Subject: Re: ep Driver and the 3c509B-TPO Message-ID: <199501190943.KAA15199@pax.inria.fr> In-Reply-To: your message of Wed, 18 Jan 1995 16:04:44 CST.
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: awd@ddg.com (Andrew W. Donoho) wrote:
>>Roger and FreeBSD folks,
>>
>>You wrote:
>>>You should be able to boot DOS and run the 3C5X9cfg.exe program
>>>and disable auto-sensing; you can select whether you want the
>>>AUI, TP, or Coax on combos; or AUI/TP, AUI/Coax on other cards.
>>
>>Thanks for the suggestion...
>>
>>I tried that but since this card only supports 10baseT, the Autosensing is
>>permanently on. The config program you suggested will not allow me to
>>change that setting.
>
>I have just gotten off of the phone with 3com tech support (impressive
>support for a $99.00 board). We jointly discovered a way to get around
>their limitations for the Autosensing. You do it by saving your current
>settings to a .set file and then edit with a text editor. When you reload
>it, it doesn't bother to "validity check" the input. If there is interest,
>I would be happy to provide my settings file to the net.
>
>Once this has been done, the card is identified and apparently turned on...
>The install floppy kernel then crashes with a "Fatal Trap 12: page fault
>while in kernel mode"
>
>fault virtual address = 0x6d6d6d6d
>fault code = supervisor read, page not present
>instruction pointer = 0x8:0xf010bb91
>code segment = base 0x0, limit 0xfffff, type 0x1b
> = DPL 0, pres 1, def32 1, gran 1
>processor eflags = interrupt enabled, resume, IOPL = 0
>current process = 0 (swapper)
>interrupt mask = net tty
>panic: page fault
>
>So when I reset the autosensing function, the kernel no longer crashes but
>I'm back to the system booting but not using the card. The initial boot
>does not find it but allows you to specify it when it gets to the network
>install phase.
>
>So, I now think that we have a problem with the fact that the 3c509b card
>has twice the buffer space of the previous edition (4K -> 8K). Anybody else
>seeing these problems???
As long as the buffer size is concerned, it should not be any problem
because the real buffer size is not considered by the ep driver but the one
reported by the card trough e.g.:
in epstart() =>
...
if (inw(BASE + EP_W1_FREE_TX) < len ...) {
^^^^^^^^^^^^^^^^^^^^^^^^
...
and for epread() =>
you would be able to read more packets (bytes) before finding there is
no more to read.
Certainly with a bigger Tx/Rx buffer, you will have to experience
lesser TxUNDERRUN and RxOVERRUN errors than before and that will increase
performance, mainly at high CPU load or with a not too powerful CPU.
Andres
------------------------------
INRIA Sophia-Antipolis, France
avega@pax.inria.fr
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