Re: accel handling

Stephen C. Tweedie
1999-08-31T18:44:35Z

Hi,

On Tue, 31 Aug 1999 13:10:46 -0400 (EDT), James Simmons
<jsimmons@edgeglobal.com> said:

>> Yes. The biggest problem is that the VM currently has no support for
>> demand-paging of an entire framebuffer region, and taking a separate
>> page fault to fault back the mapping of every page in the framebuffer
>> would be too slow. As long as we can switch the entire framebuffer in
>> and out of the mapping rapidly, things aren't too bad.
>>

> So if this is the problem could we write a special routine that optimizes
> this. What if we gave the VM support for demand paging of an entire
> framebuffer region.

You cut out the most important part of my email, which was that such
support would be prohibitively expensive for any graphics-intensive
applications. It is only feasible if there is a very low rate of
switching between accel and framebuffer access.

--Stephen