Re: [ubuntu-uk] ubuntu 16.04 fsck and display issue

[Liam Proven]

On 10 August 2016 at 16:45, David Goldsbrough  wrote:
> Well, I tried the suggestion to no effect.  I have looked through the logs
> but cannot find any hints - but I am not that experienced and my low vision
> can miss things.


Sorry to hear that you're having problems.

Here is how to both temporarily try, and permanently add, kernel boot
parameters:

https://wiki.ubuntu.com/Kernel/KernelBootParameters

Here are some instructions specific to adding "nomodeset":

http://askubuntu.com/questions/38780/how-do-i-set-nomodeset-after-ive-already-installed-ubuntu

Plymouth is the program that displays the graphical loading screen. It
is run by the kernel early in the boot up process. It runs from the
initrd, so before the hard disk has even been mounted.

https://www.freedesktop.org/wiki/Software/Plymouth/

Plymouth uses a kernel feature called KMS: kernel mode setting. This
allows the kernel to set the screen into graphics mode long before
X.org runs and the GUI starts.

https://wiki.archlinux.org/index.php/kernel_mode_setting

This can cause problems on some machines. Some of my machines display
the Plymouth graphics very early and the dots underneath the logo
animate for some time. Some display it very late and only for a short
time -- a second or so. Some do not display it at all, or only at
shutdown, often with colours distorted or the wrong palette.

But Plymouth is just decorative. You can remove it if you prefer. To
do so, replace the "splash" parameter in the GRUB entry with
"nosplash". If you want to see the kernel boot messages as they go
past, remove the "quiet" parameter.

http://askubuntu.com/questions/33416/how-do-i-disable-the-boot-splash-screen-and-only-show-kernel-and-boot-text-inst

-- 
Liam Proven • Profile: http://lproven.livejournal.com/profile
Email: lpro...@cix.co.uk • GMail/G+/Twitter/Flickr/Facebook: lproven
MSN: lpro...@hotmail.com • Skype/AIM/Yahoo/LinkedIn: liamproven
Cell/Mobiles: +44 7939-087884 (UK) • +420 702 829 053 (ČR)

-- 
ubuntu-uk@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-uk
https://wiki.ubuntu.com/UKTeam/

Re: [ubuntu-uk] ubuntu 16.04 fsck and display issue

[David Goldsbrough]

I said (extract)
> To the point, when I boot now I no longer see the "Ubuntu" message in the

> > centre of the screen with the changing coloured dots underneath.   Do I
> need to tweak something to re-instate it?
> >
>
> Liam Proven said (extract)

> >>I have successfully resurrected this in the >>past by adding the kernel
> boot
> >>parameter
>
> >>nomodeset
>
> >>You can try this at boot time by pressing E on >>the GRUB menu, and
> adding it
> >>to the end of the boot line.
>
> >>If it works, you can add it to /etc/GRUB/defaults.
>
> Well, I tried the suggestion to no effect.  I have looked through the logs
but cannot find any hints - but I am not that experienced and my low vision
can miss things.

Undaunted I researched further.
I thought this thread looked promising

https://ubuntuforums.org/showthread.php?t=2321997

and I checked a few things out but I suspect it was written before 16.04.1
and .1 has corrected the bugs in part.  I noticed late it was for lubuntu
but guessed ubuntu was the same.

I am reading this at the moment
https://wiki.ubuntu.com/Plymouth
but again notice it predates 16.04

I have not ruled out it is something to do with my graphics card nvidea but
the upgrade appears to have installed the latest driver.

If I understand things correctly the boot sequence goes something like
this:-
GRUB opens the kernal using certain parameters.  The kernal(s) have been
pre-compiled during kernal updates and compilation includes ref to display
drivers so the screen post GRUB works.  If this limited understanding is
true, I am unclear when "plymouth" is called - prior to kernal opening I
guess.  If this is true, then "plymouth" can only display splash screen in
some form of monitor default mode.  But I am guessing.
Can anyone point me in the right direction to try and fix please.  I'm not
sure if it is still a formally recorded bug which I just need to await a
fix for.

Thanks
DaveG
-- 
ubuntu-uk@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-uk
https://wiki.ubuntu.com/UKTeam/