Re: Early boot became slower

[Mattia Oss <mais.toast@gmail.com>]

On Fri, Jan 27, 2017 at 10:06:09PM +0100, deloptes wrote:
> Mattia Oss wrote:
> 
> > 
> > Anyway thanks for the effort, much appreciated. :)
> 
> Perhaps you should check your plymouth install/setup. I am not ubuntu user.

[I reply here for everybody]

First of all: ok, uploading to google drive wasn't a good idea. My bad,
apologies. I made new videos and uploaded to youtube, I'll post the links.

But first let me clarify one thing because I fear that there is a big
misunderstanding here: there's no problem with the kernel per se, it
doesn't hang, there are no errors. It just prints the output slowly, or
at least slower than before. I *think* that's related to the framebuffer
(and at this point I'm fairly certain it is, will explain later).

So the point of the videos was *not* to show you the output but to show
you *where* the slowdown occurs: right after the kernel starts.
That's why the quality is not high (ok, maybe also because I suck making
videos...).

So for the ones still interested I'll post some more infos.

Since the problem started with linux-image-4.8.0-2-amd64 I'll compare
4.8.0-1 and 4.8.0-2.

Videos:
4.8.0-1 (fast):
https://www.youtube.com/watch?v=NLWB7FyV7jU

4.8.0-2 (slow):
https://www.youtube.com/watch?v=Nc1lgpdgaxQ

Kernel logs:
4.8.0-1:
https://github.com/maistoast/share/blob/master/kernel/log/4.8.0-1/dmesg_4.8.0-1-amd64

4.8.0-2:
https://github.com/maistoast/share/blob/master/kernel/log/4.8.0-2/dmesg_4.8.0-2-amd64

This is the diff of both changelogs:
https://github.com/maistoast/share/blob/master/kernel/cl/linux-image-4.8.0-amd64-changelog.linux.diff

I saw some reference to radeon but I didn't find anything really useful.

I tried, I think, every suggestions you all gave me. If I don't post
the results it's because it didn't work. For example, plymouth (I don't
have it installed), various kernel options (vga, video, splash, etc...).

BUT, I made a progress. :)
I installed linux-source-4.9 and compiled the kernel with the 4.8.0-1
config. The result: it boots fast! :)

This is the kernel log of the custom kernel:
https://github.com/maistoast/share/blob/master/kernel/log/4.9.2/dmesg_4.9.2--bymattia

As you can see it uses simplefb and not vesafb. I'm quite sure that this
is the problem. As Sven Joachim pointed out, the Debian devs disabled
simplefb because it has problems with KMS framebuffer. Reading the link
he provided they disabled the X86_SYSFB and FB_SIMPLE options to fix
some bugs. I think there's no solution for me because these options are
not enabled in the Debian kernel anymore.. :/ 

Se either I use a custom kernel, or I keep my sweet fat characters with
the Debian kernel.

Thanks,
Mattia.