Subject: Re: Why not track our xsrc with X11R6.6 from X.org?
To: Simon Burge <email@example.com>
From: Todd Vierling <firstname.lastname@example.org>
Date: 07/19/2001 22:53:02
On Wed, 18 Jul 2001, Simon Burge wrote:
: I'm currently doing some work towards this. The basic structure is to
: add ioctl's at the wsdisplay/wscons level to deal with:
: 1) Determining the framebuffer bus type, location and identity. An
: example is:
: "pci:1:0:0 i:0x4c461002 s:0x00cc1028 c:0x03000002"
: 2) Determining allowable mmap()able ranges and handle mapping them.
: 3) Provide bus-dependant access - the only one implemented so far is
: pci config space reads and writes.
: Most of the rest of the work is in the X server itself, mainly just
: generalising device configuration to use the new ioctls. At the moment
: I'm targeting PCI devices, so the X server doesn't need to scan the PCI
: bus(es) looking for framebuffers - it just knows that it can get all the
: info from the wscons device.
From what I've gleaned from this and other discussions, what we need is a
kernel interface that does exactly three things:
1. determine the mmap-allowable data area of a card
2. arbitrate writes to control registers
3. validate DMA values used in control registers before an actual write to
those registers is performed
This shouldn't be a difficult thing, but it would likely require that XFree
supply some level of abstraction to make (2) and (3) work -- because the
hardware vendor needs to write the code for (2) which will call our supplied
hooks for (3).
-- Todd Vierling <email@example.com> * Wasabi NetBSD: Run with it.
-- NetBSD 1.5 now available on CD-ROM -- http://www.wasabisystems.com/