From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 1/2] of: Fix DMA mask generation Date: Fri, 11 Aug 2017 19:56:41 +0200 Message-ID: <20170811175641.GA1921@lst.de> References: <0819179085df6c41c70e83a2c5c138b95c0386b3.1502468875.git.robin.murphy@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <0819179085df6c41c70e83a2c5c138b95c0386b3.1502468875.git.robin.murphy@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Robin Murphy Cc: robh+dt@kernel.org, frowand.list@gmail.com, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, hch@lst.de, m.szyprowski@samsung.com, stefan.wahren@i2se.com, afaerber@suse.de, hverkuil@xs4all.nl, johan@kernel.org List-Id: devicetree@vger.kernel.org On Fri, Aug 11, 2017 at 05:29:56PM +0100, Robin Murphy wrote: > Historically, DMA masks have suffered some ambiguity between whether > they represent the range of physical memory a device can access, or the > address bits a device is capable of driving, particularly since on many > platforms the two are equivalent. Whilst there are some stragglers left > (dma_max_pfn(), I'm looking at you...), the majority of DMA code has > been cleaned up to follow the latter definition, not least since it is > the only one which makes sense once IOMMUs are involved. I think it always was supposed to be the latter, but that doesn't mean that everyone got the message :) > Either of these patches alone should be sufficient to un-break RPi3, > and they apply independently, so I'm quite happy for one to go in as a > fix now and the other to wait for 4.14. This one is something I'm comfortable feeding to Linus for 4.13 if I get a few ACKs from people familar with the OF code and intended meaning of the ranges in the device tree.