netdev - Re: [patch 1/6] pasemi_mac: Move RX/TX section enablement to dma

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Date:	Tue, 26 Feb 2008 08:14:20 -0600
From:	Olof Johansson <olof@...om.net>
To:	Michael Ellerman <michael@...erman.id.au>
Cc:	netdev@...r.kernel.org, pasemi-linux@...abs.org, jgarzik@...ox.com,
	linuxppc-dev@...abs.org
Subject: Re: [patch 1/6] pasemi_mac: Move RX/TX section enablement to
	dma_lib

Hi,

On Tue, Feb 26, 2008 at 10:46:06PM +1100, Michael Ellerman wrote:
> On Wed, 2008-02-20 at 20:57 -0600, Olof Johansson wrote:
> > +	i = 1000;
> > +	pasemi_write_dma_reg(PAS_DMA_COM_RXCMD, 0);
> > +	while ((i > 0) && (pasemi_read_dma_reg(PAS_DMA_COM_RXSTA) & 1))
> > +		i--;
> > +	if (i < 0)
> > +		printk(KERN_INFO "Warning: Could not disable RX section\n");
> > +
> > +	i = 1000;
> > +	pasemi_write_dma_reg(PAS_DMA_COM_TXCMD, 0);
> > +	while ((i > 0) && (pasemi_read_dma_reg(PAS_DMA_COM_TXSTA) & 1))
> > +		i--;
> 
> This kind of caught my eye, is it still going to work when the next core
> is twice as fast?

Actually, I added the variable right before posting, I used to have an
infinite loop there while testing the patch. I've never seen it do more
than a few rounds, so I'm not that worried.

We already have a similar loop in the channel shutdown code, but it runs
a bit longer. I might bring that over instead. Thanks for pointing it
out.


-Olof

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