Smooth graphics mode transition from GRUB to kernel

Colin Watson cjwatson at
Mon Aug 10 11:29:14 UTC 2009

On Mon, Aug 10, 2009 at 12:12:48PM +0100, Matthew Garrett wrote:
> On Mon, Aug 10, 2009 at 11:31:13AM +0100, Colin Watson wrote:
> > This doesn't seem like it ought to be an inherent limitation; several
> > architectures start up with nothing but a framebuffer, after all. I'm
> > wondering if we're just not programming the boot parameter structure
> > quite right in GRUB, or perhaps if there's some configuration tweak that
> > the kernel needs to support this. Can anyone see anything wrong with the
> > attached patch when applied to the current grub2 package in Karmic?
> > loader/i386/linux.c is the key file.
> KMS-based framebuffers are accelerated and may set up stuff like tiling, 
> so you don't necessarily have a nice, easy linear framebuffer. Grub will 
> have programmed a vesa mode which *is* a nice, easy linear framebuffer - 
> but you'd then need to bind vesafb to it right at the start of kernel 
> boot and swap from that to the native driver. It's not actually a 
> terribly easy problem.

I was wondering about adding some vid_mode constants in the
0x0f00-0x0fff range that basically meant "load KMS+fbcon as early as
possible please since we're already in graphics mode". Is that viable at
all or is it too hard to make that work early on?

Colin Watson                                       [cjwatson at]

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