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

Michael Büsch m at bues.ch
Wed Aug 24 12:06:11 EDT 2011


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?

-- 
Greetings, Michael.



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