Subject: Re: mmap'ing framebuffer memory in MI drivers...
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: Eduardo E. Horvath <>
List: tech-kern
Date: 03/04/1999 09:00:04
On Wed, 3 Mar 1999, Jonathan Stone wrote:

> oops, missed this:
> >I will assert (again) that mapping the device registers is an inherently
>                                                ^^^^^^^^^
> >bus-specific operation and should be done by the driver through the use of
> >bus_space*() routines rather than the VM system.
> I'm talking about mapping device *memory*, not registers.  if an app
> is going to map the memory and treat it like memory-- e.g., to blit
> into it -- then it better behave like memory once it's mapped,
> (at both  the  bus_space and d_mmap level!)
> Device registers are (or can be) another kettle of fish:
> memory barriers, &c.

I suppose I should have said device registers and DMA regions, since they
have similar issues with memory barriers, cache flushes, non-cacheability,

Eduardo Horvath
	"I need to find a pithy new quote." -- me