[RFT][PATCH] b43: use 8K buffers for 64-bit DMA to workaround hardware bug

[Larry Finger]

On 08/24/2011 11:06 AM, Michael Büsch wrote:
> On Wed, 24 Aug 2011 17:57:18 +0200
> Rafał Miłecki<zajec5 at gmail.com>  wrote:
>
>> +	/* For unknown reasons - possibly a hardware error - the BCM4311 rev
>>   	 * 02, which uses 64-bit DMA, needs the ring buffer in very low memory,
>>   	 * which accounts for the GFP_DMA flag below.
>> -	 *
>> -	 * The flags here must match the flags in free_ringmemory below!
>>   	 */
>> +	gfp_t flags = GFP_KERNEL;
>>   	if (ring->type == B43_DMA_64BIT)
>>   		flags |= GFP_DMA;
>
>
> Did somebody actually re-evaluate this?
> I still believe that this is not a hardware error, but rather a software
> bug in the DMA allocator that probably is fixed already.
>
> Larry, I think you added this. Do you still have the device that triggered this?

Yes, I do. I'll test the BCM4311 with the GFP_KERNEL flag.

Larry