Intel 82550 Pro/100 Ethernet and Microcode

[Adrian Chadd]

Hi!

That's actually a really good catch!

yongari/jfv, what do you think?


Adrian

On 8 March 2012 16:01, Andreas Longwitz <longwitz at incore.de> wrote:
> Hi,
>
> recently I installed FreeBSD 8.2 Stable on some older machines with
> Intel 82550 and 82550C and found that the loading of microcode with the
> parameter link0 in the ifconfig command did not work anymore. The reason
> for this is the commit r223608 for if_fxp.c with the comment:
>
> Disable microcode loading for 82550 and 82550C controllers. Loading
> the microcode caused SCB timeouts.
>
> I do not agree with this motivation and try to explain why.
>
> Without loading the microcode on 82550(C) there is a problem with
>   mount_nfs -U server:/bigdisk /mnt
>   cp /mnt/bigfile bigfile
>
> NFS with UDP works with 8 KB blocks and the cp hangs after some seconds
> and you see SCB messages on the console. The reason is the TCO bug of
> the hardware mentioned in rcvbundl.h. This old hardware bug disappears
> after loading the microcode.
>
> All my hardware run without problems in FreeBSD 4.11, loading of
> microcode is done by the function fxp_load_ucode(). Later there was
> trouble with the loading of microcode, see kern/103332 and kern/118909.
> I have posted my solution for the problem to kern/103332 but
> unfortunately this PR is not online anymore and so I repeat my
> considerations here.
>
> The difference of the function fxp_load_ucode() of FreeBSD 4.11 and
> later versions is that this function in 4.11 has an own private memory
> buffer for construction of the microcode message. In later versions
> fxp_load_ucode() must use a memory buffer that is shared with other
> parts of the driver and these other parts of the driver have problems if
> the shared memory buffer was used by fxp_load_ucode() before. Thats the
> reason for "Loading microcode caused SCB timeouts".
>
> Therefore my proposal is to revert r223608 and to clean the used shared
> buffer at the end of the function fxp_load_ucode(). The following patch
> works for me for years now:
>
> --- if_fxp.c.orig       2012-01-26 12:43:09.000000000 +0100
> +++ if_fxp.c    2012-03-08 23:41:32.000000000 +0100
> @@ -3085,6 +3081,7 @@
>            sc->tunable_int_delay,
>            uc->bundle_max_offset == 0 ? 0 : sc->tunable_bundle_max);
>        sc->flags |= FXP_FLAG_UCODE;
> +       bzero(cbp, (uc->length + 2) * sizeof(uint32_t));
>  }
>
>
> --
> Dr. Andreas Longwitz
>
> Data Service GmbH
> Beethovenstr. 2A
> 23617 Stockelsdorf
> Amtsgericht Lübeck, HRB 318 BS
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