From: Gerhard Jaeger <g.jaeger@sysgo•com>
To: linuxppc-dev@ozlabs•org
Cc: linuxppc-embedded@ozlabs•org
Subject: Re: Power PC 440GX Jumbo Packets EMAC2/3
Date: Thu, 24 Feb 2005 13:19:06 +0100 [thread overview]
Message-ID: <200502241319.07031.g.jaeger@sysgo.com> (raw)
In-Reply-To: <C18BA5DDB58DD511BD0700C0DF0DD450294284@NTSERVER4>
On Thursday 24 February 2005 12:46, zDL Linux PPC wrote:
> I have been doing some experiments with Jumbo packets (MTU 9000) and have
> noticed that once you exceed the 2KB fifo size, I end up with no response
> from the box.
>
> I can ping the box with no problem at all at sizes greater than 2KB, however
> upon further investigation I noticed packets of size 2006 bytes causes no
> further packet to be transmitted (adding debug prints to ibm_emac_core.c,
> the driver believes the packet has been transmitted), after adding a further
> 42 bytes of header information this comes to the exact size of the Transmit
> Fifo 2048 (2KB). I have also changed the Transmit Fifo Register to 1024
> bytes, this solves the problem at 2006 bytes however now it has moved to 982
> bytes of data (+42bytes of header = 1024)
>
> Has anyone else experienced this problem while either using a smaller
> transmit fifo (512 or 1024 bytes) and MTU 1500 or a larger MTU (>2033) and
> EMAC transmit fifo of 2048. I guess this will really apply to people with
> larger MTU not many will decrease the Tx fifo, and I am further guessing
> that not many are using 9000 MTU as not much hardware seems to support it, I
> can only use it through a direct connection between PC's and not through a
> switch!
>
> Any suggestions on how to overcome this problem??? My only idea is to either
> add data to the packet (don't think this will work) or forceably fragment
> the packet (if it is 2K in size) to ensure that it never uses the exact size
> of the tx fifo.....
Have you applied Matt Porters patch? It has been submitted at the beginning
of this month?
Gerhard
--
Gerhard Jaeger <gjaeger@sysgo•com>
SYSGO AG Embedded and Real-Time Software
www.sysgo.com | www.elinos.com | www.pikeos.com | www.osek.de
next prev parent reply other threads:[~2005-02-24 12:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-24 11:46 Power PC 440GX Jumbo Packets EMAC2/3 zDL Linux PPC
2005-02-24 12:19 ` Gerhard Jaeger [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-02-24 13:12 zDL Linux PPC
2005-02-24 13:45 ` Gerhard Jaeger
2005-02-24 13:55 zDL Linux PPC
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200502241319.07031.g.jaeger@sysgo.com \
--to=g.jaeger@sysgo$(echo .)com \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=linuxppc-embedded@ozlabs$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox