Re: USB and DMA on Alpha with 2.6.0-test7

[Ivan Kokshaysky]

On Fri, Oct 10, 2003 at 12:43:24PM -0700, David Brownell wrote:
>  static inline int
>  dma_supported(struct device *dev, u64 mask)
>  {
> -	BUG_ON(dev->bus != &pci_bus_type);
> -
> -	return pci_dma_supported(to_pci_dev(dev), mask);
> +	/* device can dma, using those address bits */
> +	return dev->dma_mask
> +		&& (mask & *dev->dma_mask) == *dev->dma_mask;
>  }

This doesn't work. You will always return success if mask = ~0ULL.
But more important thing is that dma_supported() must not expect
valid *dev->dma_mask, as it's called from dma_set_mask().
That is, your usage of dma_supported() is buggy regardless of
DMA API implementation.

Ivan.
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