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

[David Yang]

patch-6220/1   can't be  patched on kernel version linux-2.6.33-arm1.

the file arch/arm/mm/cache-l2x0.c  may be too old for the patch.


On Thu, Jul 15, 2010 at 6:09 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> 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.
>