From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Thu, 20 Mar 2014 12:02:36 +0100
Subject: [PATCH RESEND v2 1/2] ARM: ixp4xx: Make dma_set_coherent_mask
 common, correct implementation
In-Reply-To: <m31txxjjrj.fsf@t19.piap.pl>
References: <20140317144016.0508cc4d@marrow.netinsight.se>
 <20140320090330.49a1d372@marrow.netinsight.se> <m31txxjjrj.fsf@t19.piap.pl>
Message-ID: <201403201202.37065.arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thursday 20 March 2014, Krzysztof Ha?asa wrote:
> Simon K?gstr?m <simon.kagstrom@netinsight.net> writes:
> 
> > Thanks. However, Krzysztof thinks that this implementation is
> > incorrect. It certainly fixes my ixp4xx issues, but might not be good
> > for everyone.
> 
> It because you don't have PCI devices setting coherent mask to 32-bits
> (and that's what normal PCI devices do).
> 
> BTW PCI (and other) devices requesting 32-bit coherent allocs don't care
> if they're given 26-bit memory. 26 bits fit perfectly in 32 bits. It's
> the streaming mapping which is (may be) constrained by hardware.

Should I revert the patch then until we have a better fix?

	Arnd