Comment 8 for bug 71030

I'm having the same problem, using one nVidia card with two monitors (laptop monitor + external LCD screen connected through d-sub contact), running Ubuntu 7.10.

It has always worked before, but today, the laptop screen goes black after gnome-screensaver starts, and stays black. I can only see the mouse cursor. The other monitor works fine.

Running gnome-screensaver-preferences gives me:

The program 'gnome-screensaver-preferences' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadMatch (invalid parameter attributes)'.
  (Details: serial 343 error_code 8 request_code 78 minor_code 0)

It is the same after I do "killall gnome-screensaver". Running glxinfo gives:

name of display: :0.0
X Error of failed request: BadMatch (invalid parameter attributes)
  Major opcode of failed request: 78 (X_CreateColormap)
  Serial number of failed request: 13
  Current serial number in output stream: 15

As far as I know, I haven't changed anything since yesterday, when it worked, except for installing gdesklets.