Re: [PATCH] PCI: Add pci shutdown ability

Lee Revell
2005-04-26T17:24:15Z

On Tue, 2005-04-26 at 13:12 -0400, Alan Stern wrote:
> On Tue, 26 Apr 2005, Grant Grundler wrote:
>
> > On Tue, Apr 26, 2005 at 12:07:41PM -0400, Richard B. Johnson wrote:
> > > DMAs don't go on "forever"
> >
> > They don't. But we also don't know when they will stop.
> > E.g. NICs will stop DMA when the RX descriptor ring is full.
> > I don't know when USB stop on it's own.
>
> USB doesn't stop DMA on its own. It goes on forever until it's told to
> stop or it encounters an error.

Ditto sound cards. Once you start capture or playback the device will
DMA to/from the assigned area forever.

Lee