[linux-fbdev] Re: vm86 in kernel [was: vesafb...]

[James A Simmons]

On Wed, 26 Jan 2000, Aki M Laukkanen wrote:

> [Should this be on linux-fbdev only?]
> 
> On Tue, 25 Jan 2000, James A Simmons wrote: 
> > No!!!  Don't let user land have access to mode setting registers for video
> > cards. A rogue app could fry a monitor by miss programming the CRTC
> > register on purpose. 
> 
> We are not talking about any miscellaneous user-land process but the
> vesafb daemon which could set modes via VBE, svgalib or XFree4.

Okay.

> Currently it's a sad state of fact that a large portion of the cards are
> not supported under fbdev. This is why we had vesafb in the first place
> and the plan is to extend this facility. Of course the goal should be to
> write chipset specific drivers in the kernel but in the mean time, a lot
> of other cards could be supported.

This will be changing in the near future :) The problem is first the lack
of docs to write a framebuffer device. I wrote a HOWTO about this but it
needs some more work. I need to add a section on PLL clocks since this is
part most people don't understand. The second is the API is somewhat ugly
with all the extra console handling code in it. It is being slowly
cleaned up in 2.3.X. I hope this clenaup will make driver writing simple
and my HOWTO help guide the newbie.    
  
Codito, ergo sum - "I code, therefore I am"
James Simmons                                                      (o_
fbdev/gfx developer                                      (o_  (o_ //\
http://www.linux-fbdev.org                              (/)_ (/)_ V_/_
http://linuxgfx.sourceforge.net



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