Re: pci_alloc_consistent question

From: Jeff Garzik (jgarzik@mandrakesoft.com)
Date: Fri Oct 19 2001 - 16:37:45 EST


"MEHTA,HIREN (A-SanJose,ex1)" wrote:
> so, what is the conservative number ? 1MB ?

FWIW, if you need more than 1-4MB, you can use alloc_bootmem at system
boot to reserve huge amounts of contiguous memory... (not that anything
but lame hardware requires that anymore)

> -----Original Message-----
> On Fri, Oct 19, 2001 at 12:32:19PM -0600, MEHTA,HIREN (A-SanJose,ex1) wrote:
>
> > Is there any limitation on the amount of contiguous dmaable memory that
> > can be allocated using a single call to pci_alloc_consistent() ?
>
> Entirely platform dependant. On some systems the total available DMA memory
> for DMA may be as limited as 1mb, others have limits like 16mb yet other can
> support the entire 32-bit address space for DMA. So in case of doubt be
> conservative.

-- 
Jeff Garzik      | Only so many songs can be sung
Building 1024    | with two lips, two lungs, and one tongue.
MandrakeSoft     |         - nomeansno
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