Problem with dma_alloc_coherent at linux-2.6.33-arm1 , with RealView platform,board PBX-A9 and armv7 instructions.

[Russell King - ARM Linux]

On Thu, Jul 15, 2010 at 03:34:58PM +0530, Shilimkar, Santosh wrote:
> > -----Original Message-----
> > From: linux-arm-kernel-bounces at lists.infradead.org [mailto:linux-arm-
> > kernel-bounces at lists.infradead.org] On Behalf Of David Yang
> > Sent: Thursday, July 15, 2010 3:27 PM
> > To: Russell King - ARM Linux
> > Cc: linux-arm-kernel at lists.infradead.org; Ben Dooks
> > Subject: Re: Problem with dma_alloc_coherent at linux-2.6.33-arm1 , with
> > RealView platform,board PBX-A9 and armv7 instructions.
> > 
> > I have explicitly added the barrier() in my driver, but it did't work.
> > 
> > I will go on testing until solve the problem. I need more advice.
> >
> The 'barrier()' is just a compiler barrier. You should be using "mb" "rmb" 
> or "wmb"  depending on the usage.

It'd be useful if the patches which are destined for mainline get some
independent testing by people who have experienced the problem, rather
than creating their own solutions.

We can then have much more confidence in the patch which may eventually
be applied is solving problems people are seeing - and more importantly
identify any defficiencies in the patch so we don't have to repeatedly
patch the same area multiple times.