Nomodeset in grub

[A.J. Werkman]

Op 14-5-2012 16:16, Adam Jackson schreef:
> On Sat, 2012-05-12 at 21:14 +0200, A.J. Werkman wrote:
>
>> When I boot with nomodeset boot-option in runlevel 3, I expect that I
>> see a login prompt on a screen with 80*25 character positions.
> That's a reasonable conclusion if one's mental model is "nomodeset
> disables all pre-userspace video mode changes".  But that's not what it
> does.  nomodeset disables KMS support in the kernel.  It does not affect
> grub's behaviour, and it does not affect the old-style vga= options.
>
> So...
>
>> This was default in the old days and from somewhere around f12(?) this
>> changed and I had to use the nomodeset argument to get this screen
>> dimensions in text-mode. With F16 when grub2 started in text-mode this
>> also was the case. But now in the later F17-TC's I see that grub2 starts
>> in graphical mode. And now passing the nomodeset option no longer brings
>> up a 80*25 text-mode screen in runlevel 3, but gives me a much smaller
>> lettertype and more positions on the screen vertical and horizontal.
> When you do this, do you see symlinks for your video outputs
> in /sys/class/drm?  I suspect that you don't, that nomodeset has
> disabled KMS support as expected.  On that assumption, we would still
> need to explain why your text console doesn't match your expectations.
> I would bet that the answer is that grub2 does not reset the video mode
> to 80x25 before entering the kernel, and tells the upcoming kernel what
> mode it has programmed.  grub2.cfg seems to agree with me: gfxpayload is
> set to 'keep', at least on my machine that I didn't do anything special
> to.
Pretty sure if you set gfxpayload to 'text' in addition to passing 
'nomodeset' to the kernel you will get the old behaviour.


I freshly installed F17-TC5, changed gfxpayload to text and added 
nomodeset to the boot options. Then I rebuild the grub config-file with 
grub2-mkconfig.

Indeed I now have a 80*25 text screen on the console when I boot.

In  /sys/class/drm I do see symlinks though.


>
> Now whether that's a bug, I don't know, and kind of doubt.  Fewer video
> mode transitions during boot is generally preferable, and the way to do
> that is to pass grub's environment to the kernel for reuse.  So if you
> want a graphical boot menu, you have to set that up before you know
> you're going to disable KMS in the upcoming kernel, so...
>
> Besides, 'nomodeset' is a diagnostic tool, not a support path.
>
> - ajax

 From your comment I conclude, that I more or less wrongly use 
nomodeset. Can you tell me what the 'official' way is, to reach my goal?


Koos