[PATCH] x86: Introdudce a new option --force-vga

Kairui Song kasong at redhat.com
Tue Mar 5 00:24:23 PST 2019

On Mon, Mar 4, 2019 at 2:30 PM Dave Young <dyoung at redhat.com> wrote:
> On 02/28/19 at 06:07pm, Kairui Song wrote:
> > After commit 060eee58 "x86: use old screen_info if needed", kexec-tools
> > will force use old screen_info and vga type if failed to determine
> > current vga type. But it is not always a good idea.
> >
> > Currently kernel hanging is inspected on some hyper-v VMs after this
> > commit, because hyperv_fb will mimic EFI (or VESA) VGA on first boot
> > up, but after the real driver is loaded, it will switch to new mode
> > and no longer compatible with EFI/VESA VGA. Keep setting
> > orig_video_isVGA to EFI/VESA VGA flag will get wrong driver loaded and
> > try to manipulate the framebuffer in a wrong way.
> >
> > We can't ensure this won't happen on other framebuffer drivers, But
> > it's a helpful feature if the framebuffer drivers just work. So this
> > patch introduce a --force-vga options to let user decide if the
> > old screen_info should be used unconditional or not.
> It looks good to me except the option name, because vga usually means
> the specific vga video type.  But here you are enforcing to reuse the first
> kernel original video type.
> It would be better to use --reuse-video-type or --force-orig-video, etc..

Thanks for the review, the naming is not very good indeed, will update
the patch. How about just --reuse-video? This should be general enough
and clear.

Best Regards,
Kairui Song

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