From: simon.kagstrom@netinsight.net (Simon Kågström)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH RESEND v2 1/2] ARM: ixp4xx: Make dma_set_coherent_mask common, correct implementation
Date: Thu, 20 Mar 2014 12:05:00 +0100 [thread overview]
Message-ID: <20140320120500.77948552@marrow.netinsight.se> (raw)
In-Reply-To: <201403201202.37065.arnd@arndb.de>
On Thu, 20 Mar 2014 12:02:36 +0100
Arnd Bergmann <arnd@arndb.de> wrote:
> 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?
Yes, I think that would be good. Thanks to all for looking into it!
// Simon
next prev parent reply other threads:[~2014-03-20 11:05 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-17 13:40 [PATCH RESEND v2 0/2]: ixp4xx: Fix 3.7 regression for IXP4xx ethernet driver Simon Kågström
2014-03-17 13:42 ` [PATCH RESEND v2 1/2] ARM: ixp4xx: Make dma_set_coherent_mask common, correct implementation Simon Kågström
2014-03-18 14:58 ` Arnd Bergmann
2014-03-20 8:03 ` Simon Kågström
2014-03-20 9:34 ` Krzysztof Hałasa
2014-03-20 11:02 ` Arnd Bergmann
2014-03-20 11:05 ` Simon Kågström [this message]
2014-03-17 13:42 ` [PATCH RESEND v2 2/2] ixp4xx_eth: Setup coherent_dma_mask Simon Kågström
2014-03-18 7:43 ` Krzysztof Hałasa
2014-03-20 11:10 ` Russell King - ARM Linux
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