Re: Device driver, PCI, and mmapping

From: Jeff Garzik (jgarzik@mandrakesoft.com)
Date: Fri Jun 16 2000 - 00:50:05 EST


Aaron Holtzman wrote:
>
> It would seem that Jeff Garzik (jgarzik@mandrakesoft.com) said:
> > In 2.3.x/2.4.x, there is io_remap_page_range which exists for exporting
> > PCI MMIO areas to userspace. As James Simmons mentioned,
> > drivers/video/fbmem.c is an example of such usage.
>
> Are you supposed to use io_remap_page_range for all mmap'ed
> pci devices? I use remap_page_range for mmapping (look a new verb)
> a chunk of framebuffer for my Matrox g400 yuv driver, and it
> works well.

Yes, you should be using io_remap_page_range for MMIO regions such as a
framebuffer.

remap_page_range == io_remap_page_range on x86, but not on all other
platforms. That's why the current setup works for you, and for similar
drivers which do the same thing.

        Jeff

-- 
Jeff Garzik              |
Building 1024            | Free beer tomorrow.
MandrakeSoft, Inc.       |

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