RE: [PATCH 2.6.34] ehci-hcd: add option to enable 64-bit DMA support

[Yuhong Bao]

> (following thread from the ATA side) I'm with Greg on this. USB2.0 is
> quite slow on today's standard and most 64bit machines now have IOMMU
> of some kind anyway. 

Except that unfortunately, Intel with Lynnfield and Clarkdale decided 
to do market segmentation on the VT-d feature. 
This could be done because both have an integrated northbridge.
With Lynnfield, the very common Core i5 750 CPU do not support VT-d,
but the Core i7 800 series does.
With Clarkdale, the very common Core i3 500 series do not support VT-d,
but the Core i5 600 series does, except the 661.
Not to mention that in the Core 2 generation, VT-d was available only
on Q35/Q45/X38/X48 chipsets.

Yuhong Bao
 		 	   		  
_________________________________________________________________
Hotmail: Trusted email with powerful SPAM protection.
http://clk.atdmt.com/GBL/go/201469227/direct/01/--
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/