From: Eugene Surovegin <ebs@ebshome•net>
To: Andre Draszik <kernel@andred•net>
Cc: linuxppc-embedded@ozlabs•org
Subject: Re: Slab errors on 4xx (STB04)
Date: Mon, 10 Apr 2006 00:14:57 -0700 [thread overview]
Message-ID: <20060410071457.GA16898@gate.ebshome.net> (raw)
In-Reply-To: <44398BD4.60904@andred.net>
On Mon, Apr 10, 2006 at 12:33:56AM +0200, Andre Draszik wrote:
>
> Since it _seems_ to work nevertheless - is CONFIG_DEBUG_SLAB known to be
> broken on this platform?
Yes, it's very likely that CONFIG_DEBUG_SLAB is the culprit here. This
config option changes allocation alignment (it becomes not L1 cache
line aligned). For 4xx which has non-coherent L1 cache this with
almost 100% probability will break DMA, resulting in memory
corruption.
You can try changing __dma_sync() to do flush_dcache_range() even for
DMA_FROM_DEVICE case. However, do this only to check this theory, not
as a permanent solution :).
--
Eugene
next prev parent reply other threads:[~2006-04-10 7:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-09 22:33 Slab errors on 4xx (STB04) Andre Draszik
2006-04-10 1:42 ` Roland Dreier
2006-04-10 7:14 ` Eugene Surovegin [this message]
2006-04-10 19:48 ` Andre Draszik
2006-04-16 1:32 ` Andre Draszik
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