Re: [PATCH 3/3] alpha, drm: Add Alpha support to Radeon DRM code

On Fri, Jun 10, 2011 at 8:20 AM, Jay Estabrook [off-list ref] wrote:

Alpha needs to have the system bus address for the device's local
memory available, so that it can be returned to user-level, where
it may be used in an mmap(). So, we make bus.addr hold the ioremap()
return for kernel use, and then we can modify bus.base appropriately.

I don't get this. why is mmap passing in an address? we don't do that anymore.

When you mmap the device node it passes back a hashed offset in the
table, that the
kernel then translates into a proper address and sets up the page tables.

So I really don't get what this patch is doing, either the
explaination of what it is doing is wrong
or it is wrong.

Dave.