Comment 31 for bug 1386534

(1)

Getting help how to make tests with upstream kernels, I did find the step,
where using NONE of the few kernels BEFORE that point I have NO xorg error,
while using ANY of the few kernels AFTER that point I HAVE xorg error.

        before 3.13 upstream 3.12.33-031233-generic has NO error

        v3.13.11.6-trusty 13-Aug-2014 and before is OK

        v3.13.11.7-trusty 18-Sep-2014 and after has the ERROR

        after 3.13 upstream 3.14.25-031425-generic has the ERROR

                    upstream 3.18.0-031800rc5-generic has the ERROR

Reinstalling a formerly purged NON-upstream Ubuntu kernel, and investigating
the release date of the kernel packages, I could verify, that the critical
kernel change step is exactly at the correspondig point.

        3.13.0-36-generic 04-Sep-2014 and before is OK

        3.13.0-37-generic 25-Sep-2014 and after has the ERROR

        3.16.0-24-generic ... has the ERROR

All of these kernels were tested with the SAME Ubuntu 14.10 systems, and the
only difference between them was that wich kernel is booted. In case of
Ubuntu 14.04 I had the critical point EXACTLY at this same place.

(2)

Intalling upstream v3.13.11.7-trusty kernel, I catched the folowing error:

        Running depmod.

        depmod: ERROR: Module 'hci_vhci' has devname (vhci) but lacks
        major and minor information. Ignoring.

        update-initramfs: deferring update (hook will be called later)

(3)

Trying out two dozens of different kernels, now I can give a bit better
description of the nature of the graphic error depending on kernel version.

3/a: except for few cases, the keyboard shortcuts work, they can invoke
programs assigned to them, ... naturally I can not use them, because I can
not see them.

3/b: almost alway the option to go Ctrl-Alt-F1 and apply Ctrl-Alt-Del is
alive, while almost never can I read anything even on the caracter terminal,
... except for the case, if the crash of the graphic view arrives a bit (few
seconds) later, and I have a narrow time slot to escape to the character
consoles.

3/c: if the crash is later, then it is exactly when I first move the mouse.

3/d: I left the most important experinece to the end:

the graphical view crash has four different states, the middle two of them
are new views for me, due to the new kernels I tried out:

    -1- as if an oldtimer CRT was not able to correctly position the
        horisontal sync, and hence the picture is horisontally rotated, and
        this state is different from all the other erratic state in that I
        can invoke and use graphical programs, hard to use, because of the
        rotation: going rightward out I arrive and enter at the left edge

    -2- as if an oldtimer CRT can not catch at all an inappropriate
        horisontal sync, far beyond its frequency limit

    -3- the essentially almost homogenous white view is patched of
        very small very intesively blinking regions

    -4- at the top a very few lines reflect the original content of the top
        unity line, but the rest is white and STILL, no blinking, ... let us
        mention, that my background is white, but NOTHING can occur in this
        area, this is a dead white area

Originally an immediate or soon -4-, and immediate or soon -1- soon -4- were
the typical scenarios.

Trying out additional kernels, the additional possibilities are: inmediate
or soon -3-, and immediate or soon -1- soon -2- soon -3-.

Perhaps I should draw a state transition picture.

Thanks for the help,
        Peter.