Why does the console freeze and NOT freeze in Linux?

Question

linux

At one time, my console constantly hung up, for example, if you go home - you come the next day - only the graphical shell works, the console hangs. I found a solution to this issue, that this is an intel firewood bug and you need to specify nomodeset. Pointed out and everything was fine.
And recently ... I'm loading - and I have an 80x25 console, there are no graphics and console fonts are not loaded - squares. I remove nomodeset - it works. I thought that again the console would hang - but no, it does not hang! Has anyone come across?
Calculate Linux 17
Linux sentry 4.4.39-calculate #1 SMP PREEMPT Mon Dec 26 14:55:34 UTC 2016 x86_64 Intel(R) Core(TM) i5-2300 CPU @ 2.80GHz GenuineIntel GNU/Linux
UPD: The rollback of intel firewood is being slowly tested. With the latest firewood (2.99.917_p20170313) hangs with a black screen. With firewood p20161118 - hangs with the text that was on the screen at that moment. Now collected p20161007.

Answer 1

The problem is just in switching modes from graphics to text and vice versa, with the graphics running. It sometimes appears not only on Intel drivers, but also on other cards, as you are lucky. But intel drivers are in the lead here. Yes, it appears very often due to the included screensaver with some kind of fractals and a very active GPU. I will not describe in detail the essence of the problem, but it is connected with the distribution of graphics memory resources in different drivers responsible for the console and Xwindow itself, and loading additional resources (buffer expansion, font loading, etc.) into the "text" (codepage) part cards. In this case, the graphics driver may well overwrite some of the information allocated by the console driver.
The easiest way out of the situation is to refuse prettiness in the console if you are using Xwindow. Choose one thing...
If the graphics (XWindow) is not running, then there are no problems with modeset!