[PATCH] usb: ehci: make HC see up-to-date qh/qtd descriptor ASAP

[Will Deacon]

On Wed, Aug 31, 2011 at 07:19:33PM +0100, Rob Herring wrote:
> On 08/31/2011 12:51 PM, Will Deacon wrote:
> > Another thing that Marc and I tried on OMAP4 was not bringing up the secondary
> > CPU during boot (by commenting out most of smp_init). In this case, I/O
> > performance was good until we tried to online the secondary CPU. The online
> > failed but after that the I/O performance was certainly degraded.
> > 
> 
> Was the SCU enabled at that point? One diff between nosmp boot and
> offlining the 2nd core would be that the SCU remains enabled in the
> latter case. I think the SCU does not get enabled for nosmp.

Our rudimentary test (printing out the SCU control register during boot)
showed that it *was* enabled for nosmp. I think this is due to the secure
world having to do that on OMAP so it's probably not true for other
platforms.

Will