From: Matthew Wilcox <matthew@wil.cx>
To: linux-ia64@vger.kernel.org
Subject: Re: __get_free_pages() problem on ia64
Date: Tue, 26 Sep 2006 16:48:31 +0000 [thread overview]
Message-ID: <20060926164831.GG5017@parisc-linux.org> (raw)
In-Reply-To: <1159283801.4407.16.camel@triumph>
On Tue, Sep 26, 2006 at 08:46:40PM +0530, Adhiraj wrote:
> I found a strange thing on ia64 platform. When I allocate pages using
> __get_free_pages() with GFP_DMA, sometimes the physical addresses of
> allocated pages fall beyond 4G.
>
> I am working on a device driver where the device does not support
> addresses above 4G and hence I have to implement bounce buffers. The
You should be using the services described in
Documentation/DMA-mapping.txt rather than allocating your own bounce
buffers.
> The dma mask for the driver is set to 64 bits using pci_set_dma_mask().
Well, that's one of your problems right there .... if your device can
only DMA up to 4GB then you should set it to DMA_32BIT_MASK.
next prev parent reply other threads:[~2006-09-26 16:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-26 15:28 __get_free_pages() problem on ia64 Adhiraj
2006-09-26 16:48 ` Matthew Wilcox [this message]
2006-09-27 5:20 ` Adhiraj
2006-09-27 11:26 ` Matthew Wilcox
2006-09-27 16:11 ` Luck, Tony
2006-09-27 16:15 ` Matthew Wilcox
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