From: Jamie Lokier <jamie@shareable.org>
To: Nicolas Pitre <nico@fluxnic.net>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
"V, Hemanth" <hemanthv@ti.com>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"Shilimkar, Santosh" <santosh.shilimkar@ti.com>,
"pierre@ossman.eu" <pierre@ossman.eu>,
saeed bishara <saeed.bishara@gmail.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: Highmem issues with MMC filesystem
Date: Fri, 19 Mar 2010 01:55:23 +0000 [thread overview]
Message-ID: <20100319015523.GD14108@shareable.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1003181205020.31128@xanadu.home>
Nicolas Pitre wrote:
> Data read from a DMA based block device is corrupted in memory and
> causing all sorts of misbehavior such as segmentation faults in user
> space, or EXT2 complaining about broken filesystem metadata.
I doubt it is related, but just in case: I've seen similar on a
no-doubt completely unrelated ARM9 system on now-ancient kernels:
occasional ext3 metadata corruption.
In my case it was due to a bug in the chip's IDE driver, which did:
1. Setup DMA address register.
2. Appropriate cache flushes.
3. Write to remaining DMA registers to start DMA.
It turned out step 1 causes the DMA controller to begin reading from
that address into an internal 128-byte FIFO, before officially
starting DMA. Moving step 2 before step 1 fixed that.
-- Jamie
WARNING: multiple messages have this Message-ID (diff)
From: jamie@shareable.org (Jamie Lokier)
To: linux-arm-kernel@lists.infradead.org
Subject: Highmem issues with MMC filesystem
Date: Fri, 19 Mar 2010 01:55:23 +0000 [thread overview]
Message-ID: <20100319015523.GD14108@shareable.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1003181205020.31128@xanadu.home>
Nicolas Pitre wrote:
> Data read from a DMA based block device is corrupted in memory and
> causing all sorts of misbehavior such as segmentation faults in user
> space, or EXT2 complaining about broken filesystem metadata.
I doubt it is related, but just in case: I've seen similar on a
no-doubt completely unrelated ARM9 system on now-ancient kernels:
occasional ext3 metadata corruption.
In my case it was due to a bug in the chip's IDE driver, which did:
1. Setup DMA address register.
2. Appropriate cache flushes.
3. Write to remaining DMA registers to start DMA.
It turned out step 1 causes the DMA controller to begin reading from
that address into an internal 128-byte FIFO, before officially
starting DMA. Moving step 2 before step 1 fixed that.
-- Jamie
next prev parent reply other threads:[~2010-03-19 1:55 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-17 13:40 Highmem issues with MMC filesystem Hemanth V
2010-03-17 13:49 ` Nicolas Pitre
2010-03-17 14:40 ` Hemanth V
2010-03-17 14:40 ` Hemanth V
2010-03-17 14:58 ` Nicolas Pitre
2010-03-17 14:58 ` Nicolas Pitre
2010-03-18 9:23 ` Russell King - ARM Linux
2010-03-18 9:23 ` Russell King - ARM Linux
2010-03-18 11:15 ` saeed bishara
2010-03-18 11:15 ` saeed bishara
2010-03-18 11:24 ` Russell King - ARM Linux
2010-03-18 11:24 ` Russell King - ARM Linux
2010-03-18 13:20 ` Nicolas Pitre
2010-03-18 13:20 ` Nicolas Pitre
2010-03-18 13:30 ` Shilimkar, Santosh
2010-03-18 13:30 ` Shilimkar, Santosh
2010-03-18 14:19 ` Russell King - ARM Linux
2010-03-18 14:19 ` Russell King - ARM Linux
2010-03-18 14:41 ` Hemanth V
2010-03-18 14:41 ` Hemanth V
2010-03-18 16:17 ` Nicolas Pitre
2010-03-18 16:17 ` Nicolas Pitre
2010-03-18 17:51 ` Russell King - ARM Linux
2010-03-18 17:51 ` Russell King - ARM Linux
2010-03-18 19:24 ` Nicolas Pitre
2010-03-18 19:24 ` Nicolas Pitre
2010-03-19 1:55 ` Jamie Lokier [this message]
2010-03-19 1:55 ` Jamie Lokier
2010-03-19 13:17 ` Nicolas Pitre
2010-03-19 13:17 ` Nicolas Pitre
2010-03-19 13:27 ` Russell King - ARM Linux
2010-03-19 13:27 ` Russell King - ARM Linux
2010-03-19 17:59 ` Nicolas Pitre
2010-03-19 17:59 ` Nicolas Pitre
2010-03-19 18:26 ` Catalin Marinas
2010-03-19 18:26 ` Catalin Marinas
2010-03-19 18:56 ` Nicolas Pitre
2010-03-19 18:56 ` Nicolas Pitre
2010-03-19 14:28 ` Hemanth V
2010-03-19 14:28 ` Hemanth V
2010-03-19 14:36 ` Shilimkar, Santosh
2010-03-19 14:36 ` Shilimkar, Santosh
2010-03-19 14:45 ` Russell King - ARM Linux
2010-03-19 14:45 ` Russell King - ARM Linux
2010-03-19 14:41 ` Catalin Marinas
2010-03-19 14:41 ` Catalin Marinas
2010-03-19 14:46 ` Russell King - ARM Linux
2010-03-19 14:46 ` Russell King - ARM Linux
2010-03-19 14:52 ` Catalin Marinas
2010-03-19 14:52 ` Catalin Marinas
2010-03-19 14:54 ` Russell King - ARM Linux
2010-03-19 14:54 ` Russell King - ARM Linux
2010-03-19 16:46 ` Catalin Marinas
2010-03-19 16:46 ` Catalin Marinas
2010-03-19 16:52 ` Russell King - ARM Linux
2010-03-19 16:52 ` Russell King - ARM Linux
2010-03-19 17:47 ` Nicolas Pitre
2010-03-19 17:47 ` Nicolas Pitre
2010-03-19 18:27 ` Nicolas Pitre
2010-03-19 18:27 ` Nicolas Pitre
2010-03-19 18:38 ` Russell King - ARM Linux
2010-03-19 18:38 ` Russell King - ARM Linux
2010-03-19 18:51 ` Nicolas Pitre
2010-03-19 18:51 ` Nicolas Pitre
2010-03-22 11:45 ` Russell King - ARM Linux
2010-03-22 11:45 ` Russell King - ARM Linux
2010-03-22 12:36 ` Nicolas Pitre
2010-03-22 12:36 ` Nicolas Pitre
2010-03-19 20:14 ` Nicolas Pitre
2010-03-19 20:14 ` Nicolas Pitre
2010-03-22 9:05 ` Hemanth V
2010-03-22 9:05 ` Hemanth V
2010-03-22 12:50 ` Nicolas Pitre
2010-03-22 12:50 ` Nicolas Pitre
2010-03-18 13:42 ` saeed bishara
2010-03-18 13:42 ` saeed bishara
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