Re: [PATCH 2/2] USB: ehci: tegra: Align DMA transfers to 32 bytes

From: rmorell
Date: Fri Dec 17 2010 - 18:53:23 EST


On Fri, Dec 17, 2010 at 03:35:27PM -0800, Greg KH wrote:
> On Sat, Dec 18, 2010 at 12:17:40AM +0100, Oliver Neukum wrote:
> > Am Samstag, 18. Dezember 2010, 00:09:40 schrieb Greg KH:
> > > I still don't like it, it feels like a hack that is not going to be able
> > > to be maintained very well.
> > >
> > > And I still think the individual drivers should be fixed...
> > >
> >
> > But they are not buggy. The USB API was written under the
> > assumption that HCDs can deal with byte level granularity and alignment.
> > Hence the network driver pass DMA-able memory with an alignment
> > that suits them.
>
> Ok, fair enough.
>
> But I still don't like that urb flag stuff as a solution to this...

Yeah, I wish I knew of a better way to store this information.
urb->hcpriv seems like a nice place for host controller-private data,
but it's used by the general ehci framework throughout the lifetime of
an URB so isn't suitable for this case.

Thanks,
Robert

> thanks,
>
> greg k-h
>
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