Re: [LIP] pci_alloc_consistent usage in x86-64 kernel

On Mon, May 31, 2004 at 03:53:24AM +0000, Sathya Prakash V wrote:
> if (hwdev == NULL || hwdev->dma_mask < 0xffffffff || no_iommu)
> 		gfp |= GFP_DMA;
> If there is no_iommu then without considering the dma_mask the GFP_DMA is 
> set and the memory allocation is limited.

Sorry, I should've caught this in the first place. That is precisely
what pci_alloc_consistent is defined to do.

From Documentation/DMA-mapping.txt:

The consistent DMA mapping interfaces, for non-NULL dev, will always
return a DMA address which is SAC (Single Address Cycle) addressable.
Even if the device indicates (via PCI dma mask) that it may address
the upper 32-bits and thus perform DAC cycles, consistent allocation
will still only return 32-bit PCI addresses for DMA.  This is true
of the pci_pool interface as well.

So, the real problem is: why are you using pci_alloc_consistent to
allocate lots of memory and why not use the streaming DMA mapping APIs
such as pci_map_single ?

	-Arun


-------------------------------------------------------
This SF.Net email is sponsored by the new InstallShield X.
From Windows to Linux, servers to mobile, InstallShield X is the one
installation-authoring solution that does it all. Learn more and
evaluate today! http://www.installshield.com/Dev2Dev/0504