Re: [PATCH][2/4] usb: only set URB_NO_TRANSFER_DMA_MAP when dma is enabled

On Fri, 25 Jan 2008, Magnus Damm wrote:

> Hi guys,
> 
> Thanks for all your help so far.
> 
> On Jan 14, 2008 11:08 AM, Magnus Damm <[email protected]> wrote:
> > usb: only set URB_NO_TRANSFER_DMA_MAP when dma is enabled
> >
> > usb_sg_init() currently sets URB_NO_TRANSFER_DMA_MAP even if dma isn't
> > enabled. This patch changes the code so URB_NO_TRANSFER_DMA_MAP gets
> > set only when dma is enabled and transfer_dma is valid.
> >
> > Signed-off-by: Magnus Damm <[email protected]>
> 
> What about this patch? Any thoughts?
> 
> This patch is needed for usb storage to work properly with ohci-sm501.
> Should URB_NO_TRANSFER_DMA_MAP really be set even if dma isn't used? I
> say not.

The URB_NO_TRANSFER_DMA_MAP setting is moot when DMA isn't used; the 
flag shouldn't even be looked at.  But if you need this patch for the 
ohci-sm501 then go right ahead; there's nothing wrong with it.

Alan Stern


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