Re: lfs 12.3-rc1: 10.4. Using GRUB to Set Up the Boot Process

On Sat, 2025-02-22 at 07:21 +0100, Hans Meier wrote:
> 
> 
> On 22.02.25 07:07, Bruce Dubbs ([email protected] via lfs-support Mailing List) wrote:
> > On 2/21/25 11:20 PM, Hans Meier ([email protected] via lfs-support Mailing List) wrote:
> > > Hello,
> > > 
> > > In '10.4.4. Creating the GRUB Configuration File' a new configuration
> > > parameter has been added: set gfxpayload=1024x768x32
> > > 
> > > Using qemu on the final image results in a black screen unfortunately.
> > > Without this parameter everything works fine.
> > > 
> > > qemu-system-x86_64 -m 800 -drive file=image.img
> > > 
> > > Was there any particular reason adding this parameter end of October 2024?
> > 
> > It's in the command explanations.
> > 
> > The set gfxpayload=1024x768x32 command sets the
> > resolution and color depth of the VESA framebuffer to be passed to the
> > kernel.  It's necessary for the kernel SimpleDRM driver to use the
> > VESA framebuffer.  You can use a different resolution or color depth
> > value which better suits for your monitor.
> > 
> > You do not have qemu set up to support this.  You can try passing
> > -vga std to qemu or just remove the gfxpayload line.
> > 
> > Also see https://www.gnu.org/software/grub/manual/grub/html_node/gfxpayload.html
> > 
> >   -- Bruce
> > 
> > 
> > 
> 
> '-vga std' on qemu seems not to work for me still a black screen. So I have
> to skip the gfxpayload line. Maybe a note in the documentation would be helpful.

I'm pretty sure it works with QEMU.  It looks like you've missed the
kernel configuration change (done at the same time when I added
gfxpayload) building the kernel.  Notably:

CONFIG_SYSFB_SIMPLEFB=y
CONFIG_DRM_FBDEV_EMULATION=y
CONFIG_DRM_SIMPLEDRM=y

The change is deliberate and I've tested it with QEMU.  I'll NOT revert
it, nor add a note telling people to skip it.

-- 
Xi Ruoyao <[email protected]>
School of Aerospace Science and Technology, Xidian University

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