Hello, Upon further investigation, I did find that it appeared that the LCD inverter was involved (had this error message from the BIOS diagnostics: LCD inverter detection FAIL 1000-0323) but that turned out not to be the real cause of the problem. The real problem was the lid switch, which somehow had been stuck. This obviously powers down the inverter and shuts down the backlight. Thus the detection that fails. The nvidia driver, in wheezy, never turns on the backlight and the screen stays dark. In jessie, the backlight turns on starting at the edges and becomes gradually brighter towards the center, like the driver is increasing the brightness and never stops (until it reaches the maximum) because it's not getting any feedback from the powered down inverter.
When this happens, it is possible to log in through the network and access the system. Loading of the nvidia driver has failed at that point and is not loaded, per lsmod. The nouveau driver, which has other problems (see bug 689748) turns on the display after the initial BIOS screen and early boot steps and then the computer works fine, except for the lock-ups that occasionally happen and the fuzzy font issues, as described in bug 689748. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org