From: "Frank Buss" <fb@frank-buss.de>
To: "'Linux Kernel Mailing List'" <linux-kernel@vger.kernel.org>
Cc: <rmk+lkml@arm.linux.org.uk>
Subject: RE: Problems with dma_mmap_writecombine on mach-pxa
Date: Wed, 23 Feb 2005 02:36:23 +0100
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 8BIT
In-Reply-To: 
Thread-Index: AcUZR1eJK15ELao0TDWR9vDxj7TZZQAAJEqg
Message-Id: <20050223013624.346885B8C4@frankbuss.de>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1083
Lines: 26

Russell King <rmk+lkml@arm.linux.org.uk> wrote:

> Since we map the whole lot in one go, if you get one page, there's no
> reason why you shouldn't get the lot.  This is why I'm wondering if
> it has something to do with your other modifications.

my colleage has found the bug: in the function dma_mmap in 
arch/arm/mm/consistent.c the call to remap_pfn_range uses 
user_size in PAGE_SIZE units, but looks like it is expected 
in bytes. When using (user_size << PAGE_SHIFT), it works.

I don't know, where to fix it: Should the lower level calls 
get the size in bytes (most function arguments in Linux 
kernel sources are not commented), this means fixing the 
dma_mmap, or should PAGE_SIZE be used, then the lower level 
functions needs to be fixed.

-- 
Frank Bu?, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/