Subject: Re: XF86 wsfb driver and wscons ioctl
To: Izumi Tsutsui <>
From: Allen Briggs <>
List: tech-kern
Date: 01/18/2005 10:47:10
On Wed, Jan 19, 2005 at 12:40:16AM +0900, Izumi Tsutsui wrote:
> > There's WSDISPLAYIO_GINFO, maybe it should be extended a little.
> I'm afraid we can't change existing ioctls for backward binary
> compatibility.

Agreed.  We could rename WSDISPLAYIO_GINFO and allocate a new ioctl
value with the same name, though.

> Maybe a new ioctl should have (mostly similar with rasops_info):
> - width per pixels
> - height per pixels
> - depth in bits
> - stride in bytes
> - ptr for mmap()
> - number of bits for red (for 15/16/24/32 bits per pel)
> - number of bits for green
> - number of bits for blue
> - which bit red starts at
> - which bit green starts at
> - which bit blue starts at


> - some bitblt functions (copy, fill etc.?)
> and more?

I don't think we should be passing code here.  When I last looked,
X does a pretty good job with acceleration.  It would take a lot
to do better, I think, unless you have some hardware support--even
then, if you have to go through a kernel interface, there will
probably be a point at which it will be cheaper to just stay in
userland and let X do it.

If there is some acceleration option, then perhaps there should be
a future WSDISPLAYIO_GACCELINFO or similar.  Most wsfb, I would
think, would not need it, and the info above is enough to get X up
and running now.  Adding acceleration could easily be added in the


 Allen Briggs           
 Wasabi Systems, Inc.