[PATCH 03/12] fs_enet: Add FEC TX Alignment workaround for MPC5121.
jcrigby at gmail.com
Fri May 8 12:36:39 EST 2009
I was having deja-vu with this and realized that I have fixed at least some
of the objections to this patch.
Wolfgang you may want to look at the patch in my 5121 git tree here:
It does runtime tx packet alignment It also has fewer ifdefs and trys to
share more code. It also has a header that explains everything including
that fact that there is not a runtime conflict sine the only other ppc that
has fec is 8xx which is not in the same family.
On Wed, May 6, 2009 at 4:42 PM, Grant Likely <grant.likely at secretlab.ca>wrote:
> On Wed, May 6, 2009 at 4:12 PM, Wolfgang Denk <wd at denx.de> wrote:
> > Dear Grant Likely,
> > In message <fa686aa40905061337w6aa82f5aj787618ba108e528f at mail.gmail.com>
> you wrote:
> >> > The FEC on 5121 has problems with misaligned tx buffers.
> >> > The RM says any alignment is ok but empirical results
> >> > show that packet buffers ending in 0x1E will sometimes
> >> > hang the FEC. Other bad alignment does not hang but will
> >> > cause silent TX failures resulting in about a 1% packet
> >> > loss as tested by ping -f from a remote host.
> >> >
> >> > This patch is a work around that copies every tx packet
> >> > to an aligned skb before sending.
> >> OUCH!
> > Yes :-(
> >> > +#else
> >> > +#define tx_skb_align_workaround(dev, skb) (skb)
> >> > +#endif
> >> Another use of #ifdef blocks. What is the multiplatform impact?
> > Hm... Can you recommend a better way to solve the problem? Suggestions
> > are welcome.
> I'd rather see a runtime selectable workaround. ie. enable it based
> on the compatible property.
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Linuxppc-dev