Subject: Re: bus_dmamap_sync not enough ?
To: Stephan Uphoff <>
From: Jason R Thorpe <>
List: tech-kern
Date: 02/11/2003 10:06:06
On Tue, Feb 11, 2003 at 12:35:01PM -0500, Stephan Uphoff wrote:

 > The i82257 driver ignores this problem and just illegally calls 
 > bus_dmamap_sync with
 > BUS_DMASYNC_POSTXXXX flags with full knowledge that the DMA might not have 
 > completed.
 > ( When it finds out that the DMA did not complete it just calls bus_dmamap_sync
 > again with BUS_DMASYNC_PREXXXX op flags)

This is not illegal... this is an acceptable/intended use of the interface
(I should know -- I designed the interface and wrote the code that you're
citing :-)

        -- Jason R. Thorpe <>