It was a clean install of Ubuntu 16.04.2 64-bit on an old laptop a few days ago. The laptop is a Toshiba Satellite L655-S5198 with only Ubuntu on it now. Its fan stopped working and suffered from overheating 2.5 years ago. Before the fan died, it was on Windows 7 Home Premium and never had this black screen problem. I replaced the fan less than a week ago, after which the laptop seemed to be working fine until the latest black screen.
The laptop worked quite well for over a day or close to two days. Then all of a sudden, the screen blacked out with a very thin edge on the left side flashing yellow light, which looked almost like LCD screen bleeding. I tried to shut down/reboot the computer from the keyboard using only terminal without access to screen. It didn't work. So the CPU might have frozen/hung up. The fan kept working though. It has happened twice already. I suppose it's something I have to address now.
The fact that it could work a day or two without any issue tells me it's not the fan. Besides, when the screen blacked out, the fan continued working. My second thought is on the graphics/video driver, which I don't know much about. I ran the command
lspci -k | grep -EA3 'VGA|3D|Display'
and got the following:
00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 02) Subsystem: Toshiba America Info Systems Core Processor Integrated Graphics Controller Kernel driver in use: i915 Kernel modules: i915
I know the laptop has an Intel integrated graphics chip. I don't know which model though. As far as I know, an Intel graphics card/chip is usually compatible with Ubuntu. I installed Ubuntu 16.04.2 on the laptop just a few days ago and did all the updates afterwards. So I suppose the drivers, including the graphic driver, are fine.
I searched for answers regarding black screen problems. Most happen during boot or immediately after boot. That isn't the issue I am facing.
Please share your expertise. Thanks.