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Re: [Xen-devel] Xen Kernel (3.0.2) breaks b44 module

To: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] Xen Kernel (3.0.2) breaks b44 module
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Fri, 12 May 2006 10:03:55 +0100
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On 12 May 2006, at 09:57, Jan Beulich wrote:

This ought to be attributed to the fact that B44 supports only 30-bit DMA addresses (and does special checking), but XenLinux doesn't have a distinct DMA zone restricted to 24-bit addresses, and both dma_alloc_coherent() and swiotlb are restricting physical addresses to 31 bits only (at least the former could certainly look at the device's DMA mask and
use that value rather than hard-coding 31).

If dma_alloc_coherent isn't doing that then it should be patched to do so. Even though it won't help right now (since Xen will reject any requests more restricted than 31 bits) it will be needed when Xen is fixed to support basket-case hardware.

 -- Keir


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