[PATCH net-next 5/7] net:fec: add support for dumping transmit ring on timeout

David Laight David.Laight at ACULAB.COM
Tue Apr 29 07:23:09 PDT 2014


From: Frank Li [mailto:lznuaa at gmail.com]
> On Tue, Apr 29, 2014 at 9:01 AM, David Laight <David.Laight at aculab.com> wrote:
> > From: Frank ...
> >> > You probably want the read and write indexes as well.
> >>
> >>                      bdp == fep->cur_tx ? 'S' : ' ',
> >>                      bdp == fep->dirty_tx ? 'H' : ' ',
> >>
> >> Above code already print read and write index. 'S', 'H'
> >
> > Gah I must be asleep!
> > Something made be think that was to do with the ring ownership bit!
> 
> I think it is same thing. If I am wrong, please tell me difference.

The ownership bit in the ring flags - that the hardware uses.
Which are printed in the next field.

I'm guessing that the reason the tx ring is 'interesting' is that there
have been bugs where the driver and hardware disagree about which entry
each should process next.
Otherwise the full tx ring is likely to be very very boring.

	David



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