Disabling drm/ttm/radeon module loading for debugging

[Pasi Kärkkäinen]

On Sun, Jan 24, 2010 at 02:29:03PM +0200, Pasi Kärkkäinen wrote:
> On Sun, Jan 24, 2010 at 07:07:22AM +1000, Dave Airlie wrote:
> > On Sat, 2010-01-23 at 18:49 +0200, Pasi Kärkkäinen wrote:
> > > On Sat, Jan 23, 2010 at 11:41:15AM -0500, Clyde E. Kunkel wrote:
> > > > On 01/23/2010 09:08 AM, Pasi Kärkkäinen wrote:
> > > >> Hello,
> > > >>
> > > >> How can I make sure drm/radeon/ttm modules are not loaded,
> > > >> until I do it manually myself?
> > > >>
> > > >> I extracted the initrd image, edited the 'init' script and
> > > >> commented out loading of the modules, repacked the initrd,
> > > >> and booted but something (plymouth? udev?) still loads the modules..
> > > >>
> > > >> I'd like to load them later manually, for some debugging purposes..
> > > >>
> > > >> -- Pasi
> > > >>
> > > >
> > > > Try adding nomodeset to the kernel line in grub.conf.
> > > >
> > > 
> > > Sorry forgot to mention that I already have nomodeset..
> > > It seems it's not enough.
> > 
> > You should be able to rmmod them with nomodeset, the driver
> > doesn't do any initialisation in that case. though you
> > should boot to runlevel 3 as once X starts the hw will
> > be initialised.
> > 
> > Then you need to load radeon with modeset=1 to override it.
> > 
> 
> What I'm trying to do here is to debug some kind of text 'offset' 
> problem when the kernel is booted as Xen dom0, under the hypervisor.
> 
> I just tried booting the kernel on baremetal, without Xen.
> 
> It seems something is initialized when the drivers are loaded 
> for the first time (automatically by most probably udev, 
> trying to blacklist them now and see if that prevents them 
> from being loaded), because there's a small 'flash' on the screen
> when udev is started. This 'flash' happens on baremetal.
> 

Ok, I just also blacklisted the radeon/drm/ttm modules in /etc/modprobe.d/
and now they aren't loaded automatically anymore.

The offset-problem still happens, so it's actually not related to radeon driver, 
it's something else.

Thanks for the help!

-- Pasi