Re: Driver for Microsoft USB Fingerprint Reader

[Greg KH]

On Mon, Jul 03, 2006 at 11:56:26PM -0400, Daniel Bonekeeper wrote:
> Maybe this is not a default on the market and is something that is
> coming... but seems that some USB controllers are coming with DMA
> capabilities:
> 
> http://www.usb.org/developers/presentations/pres0501/Augustin_DMA_Implem_Final.ppt
> http://www.semiconductors.philips.com/pip/isp1183.html

I think you are a bit confused.  Of course the USB Host controller
devices support DMA, that's how things are set up and work properly
without using a ton of CPU.  They are usually PCI devices and work quite
well and use DMA.

It's the USB devices themselves that don't and can't do any DMA
themselves.

Hope this helps explain things.

greg k-h
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/