Subject: Re: framebuffer mmap access
To: Brett D. Slager <>
From: Chris G. Demetriou <>
List: tech-kern
Date: 03/21/1999 20:36:10
"Brett D. Slager" <> writes:
> How about a new flag that can be set by the WSDISPLAYIO_SMODE ioctl:
> Mixed mmap and text access would be allowed under this mode, and a framebuffer
> driver would be able to set this mode by default.
> X servers that take advantage of accelerated features incompatible with
> simple framebuffer access would have to use WSDISPLAYIO_MODE_MAPPED.
> Also WSDISPLAYIO_MODE_SIMPLE would disable the use of features incompatible
> with simple framebuffer access by the text emulation raster driver.
> Would that take care of your compatibility problem?

It would seem ... foolish for the kernel to have a performance-related
flag set to the 'low performance' setting unless it's necessary to do
that to satisfy user request.i.e. the kernel should _never_ set a flag
in that way by default.

Rather, it might make sense to have framebffer provide an attribute to
the MI code which says "this fb can be used both ways at the same

Chris Demetriou - -
Disclaimer: Not speaking for NetBSD, just expressing my own opinion.