[haiku-development] Re: CMedia driver

  • From: Rob Judd <haiqu@xxxxxxxxxx>
  • To: haiku-development@xxxxxxxxxxxxx
  • Date: Sat, 16 May 2009 09:09:33 +1000

Axel Dörfler wrote:
Rob Judd <haiqu@xxxxxxxxxx> wrote:
Axel Dörfler wrote:
Rob Judd <haiqu@xxxxxxxxxx> wrote:
Oops, looks like we need some kernel support for ISA memory here.
I thought this was a PCI driver? Are you sure there are any actual limits imposed by that chip?
The current driver appropriates a small chunk of ISA memory for DMA. Here's a comment from the cm.c file:

/* We use the SV chip in ISA DMA addressing mode, which is 24 bits */
/* so we need to find suitable, locked, contiguous memory in that */
/* physical address range. */

Patches against the kernel to allow for that are welcome, too :-)
We need something like this (ie. a page allocation strategy) that allows for more control for the DMA buffer stuff, anyway.

I'll give that some consideration and get back to you. Long time since I looked at the kernel code...

Rob

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