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Date: Thu, 1 May 2008 11:36:18 -0400
From: Christoph Hellwig <hch@infradead.org>
To: Michael Buesch <mb@bu3sch.de>
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Subject: Re: [PATCH 0/3] Add API for weak DMA masks
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On Thu, May 01, 2008 at 04:38:15PM +0200, Michael Buesch wrote:
> This patchset adds API and one user for a "weak" dma_set_mask().
> Weak means that it will fallback to smaller masks in case the
> DMA subsystem rejects a big mask.
> Currently such rejection may happen if the driver requests a 64bit
> mask on a VIA machine, for example. dma_set_mask_weak() will fallback
> to 32bit, in that case, and tell the caller about it by modifying the
> passed mask.

Why do we need it?  Is the call to set the 32bit mask when it fails
a too big burden for the driver author?