Re: [PATCH] drm/nouveau: printk info about disabled modesetting

[Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Mon, May 02, 2011 at 04:51:14PM +1000, Ben Skeggs wrote:
> On Mon, 2011-05-02 at 00:03 +0200, Marcin Slusarz wrote:
> > On Mon, Apr 04, 2011 at 07:27:35PM +0200, Marcin Slusarz wrote:
> > > ... to make it obvious why nouveau refused to drive the hardware.
> > > 
> > > Signed-off-by: Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > > ---
> > >  drivers/gpu/drm/nouveau/nouveau_drv.c |    4 +++-
> > >  1 files changed, 3 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.c b/drivers/gpu/drm/nouveau/nouveau_drv.c
> > > index f658a04..515c656 100644
> > > --- a/drivers/gpu/drm/nouveau/nouveau_drv.c
> > > +++ b/drivers/gpu/drm/nouveau/nouveau_drv.c
> > > @@ -445,8 +445,10 @@ static int __init nouveau_init(void)
> > >  			nouveau_modeset = 1;
> > >  	}
> > >  
> > > -	if (!nouveau_modeset)
> > > +	if (!nouveau_modeset) {
> > > +		printk(KERN_INFO "nouveau: modesetting disabled by kernel parameter\n");
> > >  		return 0;
> > > +	}
> > >  
> > >  	nouveau_register_dsm_handler();
> > >  	return drm_init(&driver);
> > > -- 
> > 
> > ping
> I just wonder how this is useful.  I don't find it hard when looking at
> people's logs to scroll to the top and look at the kernel commandline.

It's not all about kernel commandline (but it's still nice to have it).
You can pass modeset=0 by modprobe.conf and there's no way to read it from
dmesg later.
It just simplifies troubleshooting by taking one of the most frequent reasons
of "nouveau does not detect my card"...

> Really, that should be done *anyway* as there are many more options that
> are relevant to what nouveau does/does not do as well...

Yes. But no other parameter silently disables whole module.

Marcin