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Re: [patch net / RFC] net: fec: increase frame size limitation to actually available buffer

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On 11/29/2016 07:35 PM, Nikita Yushchenko wrote:
> Fec driver uses Rx buffers of 2k, but programs hardware to limit
> incoming frames to 1522 bytes. This raises issues when FEC device
> is used with DSA (since DSA tag can make frame larger), and also
> disallows manual sending and receiving larger frames.
> 
> This patch removes the limitation, allowing Rx size up to entire buffer.
> At the same time possible Tx size is increased as well, because hardware
> uses the same register field to limit Rx and Tx.
> 
> Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
> ---

I recently did similar changes to the freescale/gianfar to prevent fragmentation
of (E)DSA frames [1].

With the fragmentation kicking in, I noticed a bug in the scatter-gather logic
which caused the frame-size of fragmented frames to be reported wrong [2]. Not
sure if the fec driver has SG capabilities and if this issue also applies, you
might want to double-check.


Cheers,
Zefir


[1] http://marc.info/?l=linux-netdev&m=147187438313519&w=2
[2] http://marc.info/?l=linux-netdev&m=147187430213484&w=2

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[patch net / RFC] net: fec: increase frame size limitation to actually available buffer Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2016-11-29 19:40 +0100
  Re: [patch net / RFC] net: fec: increase frame size limitation to  actually available buffer Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2016-11-30 07:40 +0100
    RE: [patch net / RFC] net: fec: increase frame size limitation to  actually available buffer Andy Duan <fugang.duan@nxp.com> - 2016-11-30 08:40 +0100
    Re: [patch net / RFC] net: fec: increase frame size limitation to  actually available buffer Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> - 2016-11-30 09:40 +0100
      DSA vs envelope frames Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2016-11-30 16:00 +0100
        Re: DSA vs envelope frames Andrew Lunn <andrew@lunn.ch> - 2016-11-30 16:20 +0100
          Re: DSA vs envelope frames Florian Fainelli <f.fainelli@gmail.com> - 2016-12-01 04:50 +0100
        Re: DSA vs envelope frames Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> - 2016-12-01 13:50 +0100
  RE: [patch net / RFC] net: fec: increase frame size limitation to  actually available buffer Andy Duan <fugang.duan@nxp.com> - 2016-11-30 11:20 +0100
  Re: [patch net / RFC] net: fec: increase frame size limitation to  actually available buffer Zefir Kurtisi <zefir.kurtisi@neratec.com> - 2016-11-30 17:20 +0100

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