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To: Richard Tobin <richard@cogsci.ed.ac.uk>
cc: Steve Passe <smp@csn.net>, multimedia@freebsd.org
Subject: Re: newest bt848 driver 
In-reply-to: Your message of "Sat, 29 Mar 1997 15:12:10 GMT."
             <27837.199703291512@pitcairn.cogsci.ed.ac.uk> 
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Date: Sat, 29 Mar 1997 12:20:33 -0800
From: Amancio Hasty <hasty@rah.star-gate.com>
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>From The Desk Of Richard Tobin :
> #define DMA_PROG_ALLOC		8
> ...
> bktr->dma_prog = get_bktr_mem(unit, DMA_PROG_ALLOC);
> 
> This appears to be allocating only 8 bytes for the DMA program???
> 
> -- Richard
> 

get_bktr_mem allocates memory in terms of pages (4096 bytes)

static vm_offset_t
get_bktr_mem( int unit, unsigned size )
{
	vm_offset_t	addr = 0;

	addr = vm_page_alloc_contig(size, 0x100000, 0xffffffff, 1<<24);
	if (addr == 0)
		addr = vm_page_alloc_contig(size, 0x100000, 0xffffffff,
								PAGE_SIZE);
	if (addr == 0) {
		printf("meteor%d: Unable to allocate %d bytes of memory.\n",
			unit, size);
	}

	return addr;
}

in /sys/vm/vm_page.c:
vm_offset_t
vm_page_alloc_contig(size, low, high, alignment)
	vm_offset_t size;
	vm_offset_t low;
	vm_offset_t high;
	vm_offset_t alignment;
{
	return ((vm_offset_t)contigmalloc(size, M_DEVBUF, M_NOWAIT, low, high,
					  alignment, 0ul));
}

	Have fun,
	Amancio