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Date: Tue, 28 Jan 2014 19:48:35 +0100
From: Beniamino Galvani <b.galvani@gmail.com>
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Subject: Re: [Qemu-devel] [PATCH v4 1/3] util/fifo8: implement push/pop of
 multiple bytes
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Stefan Hajnoczi <stefanha@gmail.com>, Peter Crosthwaite <peter.crosthwaite@xilinx.com>, QEMU Developers <qemu-devel@nongnu.org>, Li Guang <lig.fnst@cn.fujitsu.com>, Andreas =?iso-8859-1?Q?F=E4rber?= <afaerber@suse.de>

On Tue, Jan 28, 2014 at 10:43:28AM +0000, Peter Maydell wrote:
> On 28 January 2014 00:04, Peter Crosthwaite
> <peter.crosthwaite@xilinx.com> wrote:
> > On Tue, Jan 28, 2014 at 4:32 AM, Peter Maydell <peter.maydell@linaro.org> wrote:
> >>>  void fifo8_reset(Fifo8 *fifo)
> >>>  {
> >>>      fifo->num = 0;
> >>> +    fifo->head = 0;
> >>
> >> This is a bug fix, right? It should go in its own patch.
> >>
> >
> > No bug - where the ring buffer starts following a reset is undefined
> > and need not be defined. But it improves the predicatability of the
> > newly added pop_buf fn as you can now following a reset, guarantee
> > that a single pop_buf will take all contents if its the first pop
> > (which is how its being used in P2).
> 
> True. I still think it should have its own patch (and
> indeed it would be worth saying what you just did as
> part of the commit message for that patch...)

Ok, I will move the change to a new patch.

> I think it's also nicer for any state that gets migrated
> to be reset cleanly.

Do you mean also the buffer content? In the emac the tx fifo gets
reset after each transmission. Isn't this too costly?

Beniamino