Xorg -configure questions

[gene heskett]

On Thursday, February 24, 2011 02:31:26 pm Alan Coopersmith did opine:

> On 02/24/11 11:00 AM, gene heskett wrote:
> > On Thursday, February 24, 2011 01:53:16 pm Alan Coopersmith did opine:
> >> On 02/24/11 07:06 AM, lfs lfs wrote:
> >>>     From: lfs lfs <linuxfromscratch at yahoo.com>
> >>>     Subject: Xorg -configure questions
> >>>     To: xorg at lists.freedesktop.org
> >>>     Date: Thursday, February 24, 2011, 8:04 AM
> >>>     
> >>>     Hi,
> >>>     
> >>>       for example:
> >>>     ----------------------------------------------------------
> >>>     Xorg -configure  //1st flickering here
> >>>     cp -rf /root/xorg.conf.new /etc/X11/xorg.conf
> >>>     startx //2nd flickering here
> >>>     ----------------------------------------------------------
> >>>     
> >>>     This will flicker screen twice. How can I make this flicker only
> >>>     once?
> >> 
> >> Drop the first two steps and startx with no xorg.conf.
> >> 
> >> There's no point creating one if you're not going to change any
> >> settings from the defaults, just let the server run with the
> >> defaults from its autoconfiguration.
> > 
> > This is not always the magic twanger, Alan.  With no xorg.conf, it
> > insists on using the ati drivers if they are installed, for an ati
> > card.  Or the nv drivers for an nvidia card.  This is deadly to the
> > performance of an rtai based application such as emc.  So we must
> > make enough of an xorg.conf to specify the vesa driver, which has no
> > or very little effect on rtai latencies and gives us more than
> > adequate video to carve whatever we can write gcode to do. 
> > Admittedly, this is a 'narrow' application, but it should be
> > considered.
> 
> That falls under "changing the settings from the defaults" - if you read
> what I said "if you're not going to change any settings from the
> defaults" you'll see no conflicts between my advice and your
> requirements.

True, but its the defaults that ate my lunch, and wrecked a part and $20 
worth of tooling when the control response went from milliseconds to 3+ 
seconds because the wrong video driver was automatically used after a 
reboot requiring upgrade. I expected a normal reboot, entered my passwd and 
went for coffee in the house.  The screen looked normal when I returned 5 
minutes later.

> Though if you want the vesa driver, the above instructions are also the
> wrong way to do it - you wouldn't run Xorg -configure, you'd just run

Chuckle, that would be simpler had I known about it at the time, but in my 
case I found a backup-date file that was correct and copied it back.  I may 
just set the i bit on the file, simpler and I don't have to depend on 
medium term memory to fix it the next time the *buntu update mechanism gets 
uppity.  As I'm on my 77th trip around this star, the memory for such 
details seems to fade in 2 or 3 weeks of non-use. Thats a major PIMA.  :-\

My poor memory is not your fault of course...
 
> cat > /etc/X11/xorg.conf << _EOF
> Section "Device"
>         Identifier  "Card0"
>         Driver      "vesa"
> EndSection
> _EOF
> 
> Though I just ship a /usr/lib/X11/xorg.conf.vesa in my xorg packages so
> that you don't even need to that, just "Xorg :0 -config xorg.conf.vesa",
> but not all packagers do so.

Thank you Alan, I was not aware of that, and it would appear that the 
*buntu's strip that bit of usability as that file is not present on that 
machine.  Bad dog, no biscuit...  Sigh.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
<http://tinyurl.com/ddg5bz>
Lots of folks are forced to skimp to support a government that won't.