On Tue, 10 Jul 2007, Vrijaldenhoven, Serge wrote:

> Hi,
>
> I installed SL5 on a Latitude C-400. When I switch from GUI to a virtual 
> terminal (e.g. Ctrl-Alt-F2) and then back to GUI (Ctrl-Alt-F7) my system 
> completely locks up: screen gets black and no keystrike has any effect. 
> The only thing I can do then, is reboot. Is anybody experiencing the 
> same problem and is there a solution for this?

Oddly enough we have a machine where quite the oposite applies, ie one 
*must* change vt to avoid problems...

In our case the problem is with the driver for the onboard Intel 845 
graphics -- if the X server has powered the monitor down (DPMS) when one 
restarts it (with either gdm-restart or gdm-safe-restart), it leaves the 
video card in a confused state and you never get any output.  Using chvt 
to switch vt's has the side-effect of getting the X server to wake up the 
monitor and then a restart is ok.

I've never liked Intel onboard graphics chipsets and this just further 
makes me glad we have so few machines using them...

> Possibly related?:
> https://bugs.launchpad.net/fedora/+source/beryl-core/+bug/107034
> [log in to unmask]" target="_blank">http:[log in to unmask]

Those appear to be describing problems with 'beryl' or 'Desktop Effects'
(whatever those are).  If you have such things enabled does turning them 
off help?

What graphics hardware does your C400 have?  Which xorg driver is being 
used?  Can you check if the system is still accessible over a network when 
it seems to have frozen at the console?

We have some machines with particular ATI chipsets which older versions of 
X radeon driver dislike and freeze the system solid when some operations 
happen.  Our problems *seem* to be fixed in the xorg in SL5 but in earlier 
systems (XFree86 in SL3 and xorg in SL4) we had to use the SVGA driver to 
avoid the lock-ups.

-- 
Jon Peatfield,  Computer Officer,  DAMTP,  University of Cambridge
Mail:  [log in to unmask]     Web:  http://www.damtp.cam.ac.uk/