Subject: Re: Fix in if_wm.c.
To: None <>
From: Jason Thorpe <>
List: tech-kern
Date: 05/05/2004 05:50:04
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On May 5, 2004, at 4:17 AM, <> wrote:

> The ability to use MCLBYTES larger than 2048 is ifdef'd out in the wm
> driver, with the somewhat cryptic comment:
>        /*
>         * XXX MCLBYTES > 2048 causes "Tx packet consumes too many DMA"
>         * XXX segments, dropping" -- why?
>         */
> The message above is probably a result of an MD bug somewhere
> (in bus_dma_load_mbuf), the card has no problem using larger buffers.
> I have used 4096 bytes mbuf clusters on x86 with many different
> wm cards for a long time now without any problem at all, and I
> would like to turn on the ability again. Comments?

No objection from me.  Thor actually added that comment, and he 
observed the problem on x86.  *shrug*

         -- Jason R. Thorpe <>

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