Subject: Re: dmamap_sync function a no-op..?
To: Aaditya Rai <>
From: Jason R Thorpe <>
List: tech-kern
Date: 10/19/2001 08:45:08
On Thu, Oct 18, 2001 at 08:37:43PM -0700, Aaditya Rai wrote:

 > While browsing code, I realized that for  i386/pci case bus_dmamap_sync
 > function is a no-op. Is that so...? If so, why..? Is that ok for memory
 > which has not been dmamem_alloce'd with DMA_COHERENT flag... (e.g. user
 > space) ?
 > I know I'm missing something really basic here :-(

Since i386 caches are coherent wrt. DMA, there is no need for dmamap_sync
to do anything on that platform/bus combo.

        -- Jason R. Thorpe <>