rhgb and video drivers [was kernel-2.6.11-1.14_FC3 kernel and new nvidia driver]

[Rahul Sundaram]

John DeDourek wrote:

> Eric Tanguy wrote:
>
>> After that the things went worse and worse. In rhgb mode the system
>> hanged just after the devices initialization and without rhgb the system
>> hanged at swap activation. No mean to boot.
>
> [clip...]
>
> I am NOT expert in this and am trying to learn how things work by 
> reading this group,
> reading bugzilla, etc.  I have been following a bit of a discussion on 
> the rhgb thing, and
> will try to summarize:
>
> The rhgb thing was introduced to show a "prettier" view while booting, 
> perhaps thus being
> less intimidating to non-technical users.  Probably a good thing to 
> increase "market share"
> of  Linux vs. some of those "other" OS's geared to the vast majority 
> of users (who are
> NOT intending to become highly computer literate; but introduction to 
> Linux may
> change that...sorry, editorial comment...).
>
> Apparently the rhgb provides the pretty image by firing up an X server 
> early in the boot
> process, or in any case switching to graphical mode on the display 
> adapter.  However,
> the "full desktop" can't be introduced that early in the boot process. 
> If using the default
> login style (known as run level 5) then at some point the "early X 
> server" must be shut
> down and the "real X server" fired up during the boot process.  Prior 
> to FC3, it was
> done in the order just stated, i.e. stop X, start X.  Unfortunately, 
> this leaves a fraction
> of a second where the display has gone from graphical mode to text 
> mode and then
> back to graphical mode, causing an annoying flicker in the screen.
>
> Apparently, starting with FC3 (or some update of it), the order was 
> reversed.  The
> "early X server" is started on one "virtual console".  Then later in 
> the boot process,
> the "real X server" is started on another "virtual console".  Then the 
> screen is switched
> from the early to the late console; this results in very little 
> flicker because both of these
> consoles are in graphical mode.  Then the "early X server" is stopped.
>
> This, unfortunately results in a brief period when two graphical mode 
> X servers are
> running in parallel on separate virtual consoles.  Apparently this is 
> no problem for
> some video card drivers.  On the other hand, some programmers of video 
> card
> drivers never considered that the driver might be called on to 
> maintain two virtual
> consoles simultaneously.
>
> Two workarounds appear for those having trouble with the video card 
> driver handling
> the new rhgb scheme:
> -- edit grub.conf to remove the rhgb and live with the "technical 
> output" during boot
> -- change to using a text mode login (i.e. boot to run level 3); login 
> in text mode and
>    type "startx" if you want to use graphical mode.  (Is there an 
> official way to change
>    the boot run level after installation?)
>
> So that's my summary of the problem about rhgb as I understand it.  I 
> would
> appreciate any corrections to the above posted as a followup. (Note 
> that the
> original poster had a further problem after eliminating the rhgb.  I 
> don't have any
> insight into that one.)  I hope that the above might be useful to others.
>
> John D.
>

This is a pretty good summary of the current status of rhgb . It is 
planned to be removed for FC4 and start the GNOME display manager (Login 
screen) early. Here is the bugzilla URL for more details and discussions

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=151952

regards
Rahul