Re: [RFC PATCH] usb: hcd: warn about URB buffers that are not DMA aligned and are about to be DMA mapped

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On 16.06.2013 11:21, Oliver Neukum wrote:
> On Saturday 15 June 2013 16:22:30 Jussi Kivilinna wrote:
> 
>> Hm.. rethink this a bit.
>>
>> Transfer buffer might be dma aligned but shorter than cacheline and end of cacheline
>> used as something else. Manual alignment by host driver does not catch that
>> or fix that.
>> So, yes.. dma mapping should work with unaligned buffers, but maybe the actual
>> problem is multiple buffers from same cacheline.
> 
> The buffers kmalloc() returns are OK in that regard. A driver that uses
> a buffer for anything but buffering is buggy.

Ok, I'll look at that direction. Thanks.

-Jussi

> 
> 	Regards
> 		Oliver
> 
> 

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