[Bf-committers] Quicktime & autoconf

Meino Christian Cramer bf-committers@blender.org
Thu, 01 May 2003 19:28:37 +0200 (CEST)


From: Douglas Toltzman <doug@oakstreetsoftware.com>
Subject: Re: [Bf-committers] Quicktime & autoconf
Date: Thu, 1 May 2003 11:59:40 -0400 (EDT)

Hi Douglas,


> It's more likely that a feature or a bug in blender is exploiting a
> serious bug in the X-server.  

  ...why all my problems with OpenGL and such are based on blender ?
  ...why no other program exploits those bugs in the XServer ? 

> The X-server has root privilege and directly
> controls hardware (ring 0?) which would enable it to crash the system.  I
> doubt it's a kernel bug.  You said you are running a special version of
> XFree86, you might check for patches for that.  

  First I had problems with blender under XFree 4.2.0. -- no other
  program has exploited bugs in the XServer and run smoothly.
  First I had problems with blender under XFree 4.2.1. -- no other
  program has exploited bugs in the XServer and run smoothly.
  I tried 4.2.1.1 -- the problems remain, when using blender -- no other
  program has exploited bugs in the XServer and run smoothly.
  I tried 4.3.0   -- the problems remain, when using blender -- no other
  program has exploited bugs in the XServer and run smoothly.
  Then, to circumvent any mismatch of something in my old system (wrong
  lib versions and such) I built up a "Linux-from-scratch" system,
  because it was said, that /probably/ gcc would have some problems.
  The built was made from the first to the last byte only by compiling
  source of matching programs and libs with only one compiler. I could
  built the complete and newest KDE suit and Gnome suit with this
  system -- so gcc seem to be ok including any other software.
  But (guess) -- the problems remain, when using blender -- no other
  program has exploited bugs in the XServer and run smoothly.
  Somehow desperate I tried the cvs XFree snapshot 4.3.99.2 (kinda patch to
  4.3.0) -- the problems remain, when using blender -- no other
  program has exploited bugs in the XServer and run smoothly.

  You see, before I posted my problems to this list, I spent some
  effort to proof, that the problem is/is not in the XServer -- or
  seomthing else.

  What patch to the patch (cvs snapshot) to 4.3.0. should I use then?

> There is no way Blender
> can crash your system without help from X.  

  True...but that does not proof, that the Xserver is the root of all
  evil. Calling a certain routine of the libc (just for example) with
  a null pointer instead a pointer to a string will cause a failure in
  the code of the libc...even if the libc has no bug here...(it should
  check for null pointers though.)

  If the libc would have kernel previlidge, it also could hang the
  system due to that bogus call.

> There is nothing the kernel
> can do to protect your from a failing device driver.  

  True, agreed.

> Would you consider a
> different, better supported video card??? :)

  No.
  Not unless it is proofen that
  A.) the problem, is not initiated by blender
  and
  B.) the problem is initiated by the XServer and cannot be fixed
      (for example due to some propietary secrets)
  C.) my card has a hardware defect.

  This card I bought half a year ago, since it was said to me, that it
  is supported by OpenSource code and is OpenGL-able.

  I dont want to throw away the car, if the fuel is empty.

  Sorry...

  Kind regards and
  keep hacking
  Meino

> /*********************************************
>  * Douglas Toltzman
>  * President/CEO, Oak Street Software, Inc.
>  * doug@oakstreetsoftware.com
>  * http://www.oakstreetsoftware.com/
>  *********************************************/
> 
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