From: gregkh@linuxfoundation•org (Greg KH)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: mvebu: pass the coherency availability information at init time
Date: Wed, 10 Jun 2015 20:45:21 -0700 [thread overview]
Message-ID: <20150611034521.GA12809@kroah.com> (raw)
In-Reply-To: <1433992764-12753-1-git-send-email-gerg@uclinux.org>
On Thu, Jun 11, 2015 at 01:19:24PM +1000, gerg at uclinux.org wrote:
> From: Greg Ungerer <gerg@uclinux•org>
>
> This patch is specifically meant to be applied to stable tree linux-3.10.y.
Why? What's wrong with taking the exact specific upstream patches
instead?
Your descriptions here:
> IO coherency should not be used on the Armada 370 SoC, due to all
> the necessary pre-requisites for reliable operation not being met
> (such as write allocate cache policy, shareable pages, SMP bit set).
>
> Commit e55355453600a33bb5ca4f71f2d7214875f3b061 ("ARM: mvebu: disable
> I/O coherency on non-SMP situations on Armada 370/375/38x/XP") was
> intended to disable IO coherency for the Armada 370. However it only
> disables the CPU side IO coherency. The mbus driver (drivers/bus/
> mvebu-mbus.c) still passes the IO coherency attributes through the
> dram chip selects and onto driver memory window attributes. It
> does this based on looking directly into the device tree (looking
> for "marvell,coherency-fabric").
>
> To fix we pass the coherency availability information (whether enabled
> or not) to the mbus driver at init time. This is done in the same way
> that it was done for mainline kernels in commit
> 5686a1e5aa436c49187a60052d5885fb1f541ce6 ("bus: mvebu: pass the
> coherency availability information at init time").
>
> Having the IO coherency enabled on the Armada 370 SoC causes rare
> unreliable system behavior. It is not easy to consistently reproduce
> problems caused by this. Best method I have seen is heavy network
> load resulting in kernel dumps due to corrupted memory.
I don't understand the issue here, I really don't want to not take
patches that are not in Linus's tree, sorry.
greg k-h
next prev parent reply other threads:[~2015-06-11 3:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-11 3:19 [PATCH] ARM: mvebu: pass the coherency availability information at init time gerg at uclinux.org
2015-06-11 3:45 ` Greg KH [this message]
2015-06-11 4:04 ` Greg Ungerer
2015-06-11 7:25 ` Thomas Petazzoni
2015-06-11 14:51 ` Greg KH
2015-06-11 15:14 ` Thomas Petazzoni
2015-06-12 1:19 ` Greg Ungerer
2015-06-30 0:31 ` Greg KH
2015-06-30 13:09 ` Greg Ungerer
2015-06-30 16:48 ` Greg KH
-- strict thread matches above, loose matches on Subject: below --
2015-06-09 1:35 gerg at uclinux.org
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