Re: Alpha: virt_to_bus/GFP_DMA problem

Jes Sorensen (Jes.Sorensen@cern.ch)
10 Dec 1999 17:39:06 +0100


>>>>> "Andrea" == Andrea Arcangeli <andrea@suse.de> writes:

Andrea> On Fri, 10 Dec 1999, Thomas Sailer wrote:
>> Doesn't the definition of GFP_DMA imply that its bus address should
>> lie below 16M?

Andrea> No. On different alpha architectures you have different
Andrea> limits. Have a look at include/asm-alpha/dma.h. The GFP_DMA
Andrea> returns memory that must work for doing ISA_DMA.

Yes it does, ISA DMA by definition is limited to 24 bit on the bus
side afaik, it's a bit hard to feed a 64 bit address to a device which
only has space for 24 bit in it's registers.

Jes

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