[RFC] ARM: dma-mapping: outer cache is invalidated twice

[Per Forlin]

On 15 February 2011 16:46, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Tue, Feb 15, 2011 at 04:11:09PM +0100, Per Forlin wrote:
>> True. In my case write back is disable but read back is enable, that's
>> why I didn't consider it.
>
> What do you mean "write back is disable" ?  You can only prevent
> writebacks by using a write-through cache.
>
I meant "no write allocate"

> Any writeback cache, whether in read-allocate or read-write-allocate
> mode will have writebacks.
>
Yepp, this is where I jumped to conclusions. I thought there would be
no writebacks if using "no write allocate". Now that I look at the
cache documentation again it feels so obvious.

Thanks for explaining this to me,
Per