Date: Wed, 23 Mar 2016 12:51:28 +0100
From: Joerg Roedel <joro@8bytes.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>, grant.likely@linaro.org,
        devicetree@vger.kernel.org, jroedel@suse.de,
        Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org,
        iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 6/6] iommu/arm-smmu: Make use of phandle iterators in
 device-tree parsing
Message-ID: <20160323115128.GB17838@8bytes.org>
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Hi Robin,

On Tue, Mar 22, 2016 at 06:53:48PM +0000, Robin Murphy wrote:
> In a stream-matching implementation, a device may quite legitimately
> own anything up to _all_ of the stream IDs (32768, or 65536 if we
> ever implement support for the SMMUv2 EXID extension), so this is
> only a genuine limit for stream indexing (and if anyone ever
> actually made one of those, I don't think they're running mainline
> on it).

Do you mean we might see a lot more than the currently 128 supported
stream-ids for an smmu?

> Alternatively, how straightforward is it to change the DT on your
> machine? I'll be getting a v2 of [1] out in a couple of weeks (after
> imminent holidays), which already gets rid of MAX_MASTER_STREAMIDS
> altogether, and might also have grown proper SMR support by then.

Hmm, I don't know how to change the DT of this Seattle machine. I think
it is provided by the ACPI BIOS. At least it boots with grub2 and not
u-boot and there is no DT in /boot.


	Joerg