kdm-trinity (V3.5.12) timing out before X starts

Hi, I'm frequently experiencing a problem with kdm-trinity (V3.5.12) appearing to time out on system start-up. The following two lines are put into my syslog when this happens: kdm[1966]: X server startup timeout, terminating kdm[1966]: X server for display :0 can't be started, session disabled This is an intermittant problem and doesn't happen every time I start my system (I'd guess it occurs about 50% of the time). When it does I'm left with just the basic console. However, all I need to do to get X up and running is to log in on the console and restart kdm-trinity. The system is running Debian Squeeze on amd64 with an nVidia graphics card using the proprietary nVidia driver. Curiously, I don't recall this happening when I first installed TDE V3.5.12, which was quite some time ago now and it only seems to have started occurring relatively recently. Since I first installed Trinity V3.5.12 I have installed a number of Debian Squeeze updates but in addition to this I also tried upgrading to TDE V3.5.13 but then had to downgrade back to TDE V3.5.12 due to a couple of problems with V3.5.13. As I didn't remove TDE V3.5.13 and all of its config files when I downgraded back to TDE V3.5.12 I imagine that it's possible that kdm-trinity V3.5.13 introduced some different configuration settings. Alternatively, there have been a couple of kernel updates during this period (I compile my own kernels from the Debian linux-source package and then need to recompile the nVidia driver to fit the new kernel. The kernel updates have all been minor point updates so the kernel configs have been unchanged over the period concerned) and this may be a factor. Fwiw, the syslog messages from kdm-trinity appear about 15 seconds after the nVidia module load message. I've also had a look in the Xorg.log files and while there are no clear errors or warnings there are differences at the end of the logs between successful and unsuccessful start ups as shown below... Unsuccessful startup: (**) Option "xkb_rules" "evdev" (**) Option "xkb_model" "pc105" (**) Option "xkb_layout" "gb" (II) Power Button: Close (II) UnloadModule: "evdev" (II) Power Button: Close (II) UnloadModule: "evdev" (II) AT Translated Set 2 keyboard: Close (II) UnloadModule: "evdev" (II) ImExPS/2 Generic Explorer Mouse: Close (II) UnloadModule: "evdev" (II) ACPI Virtual Keyboard Device: Close (II) UnloadModule: "evdev" Successful startup: (**) Option "xkb_rules" "evdev" (**) Option "xkb_model" "pc105" (**) Option "xkb_layout" "gb" (II) Open ACPI successful (/var/run/acpid.socket) (II) Feb 15 11:52:58 NVIDIA(0): Setting mode "1920x1200+0+0" (II) Power Button: Device reopened after 1 attempts. (II) Power Button: Device reopened after 1 attempts. (II) AT Translated Set 2 keyboard: Device reopened after 1 attempts. (II) ImExPS/2 Generic Explorer Mouse: Device reopened after 1 attempts. (II) ACPI Virtual Keyboard Device: Device reopened after 1 attempts. The extract from the unsuccessful start up clearly shows that some of the devices are being closed but I can't see any reasons why and, as I say, there are no errors or warnings: apart from some different time-stamps earlier on in the logs they are otherwise identical (according to KDiff3). Any hints or tips would be appreciated. Regards, LeeE